ArticleLiterature Review

Tachycardiomyopathy: mechanisms and clinical implications

Authors:
  • Cardiovascular research center aalst belgium
To read the full-text of this research, you can request a copy directly from the authors.

No full-text available

Request Full-text Paper PDF

To read the full-text of this research,
you can request a copy directly from the authors.

... Early recognition of this entity and its treatment by eliminating the arrhythmogenic trigger are crucial to prevent haemodynamic instability and chronic irreversible changes limiting full recovery of myocardial function. [1][2][3] Atrial flutter is recognized among the causes of TCM, with a prevalence of around 9% in patients referred for ablation. 4 In view of the high success rate and the low risk of complications, ablation of the cavotricuspid isthmus (CTI) is the treatment of choice when atrial flutter and TCM are suspected. ...
... TCM is a ventricular dysfunction in response to rapid and/or asynchronous or irregular myocardial contraction, partially or completely reversible after An early diagnosis of TCM is valuable because of the potential for recovery with appropriate treatment, specifically treating the proarrhythmic trigger. [1][2][3] The presence of a LAA thrombus excluded the possibility to perform a direct ECV. Given the less concealed conduction into the atrioventricular node (and therefore more difficult rate control) of the atrial flutter, a rate control strategy has often limited success. 1 Thrombus entrapment with LAA closure ...
... of heart failure observed treatment of the arrhythmic trigger and not instantaneous.[1][2][3] The diagnosis may only be confirmed ex juvantibus. ...
Article
Full-text available
Background The etiological spectrum of heart failure with reduced ejection fraction is various. Tachycardiomyopathy is recognized as one of the cause, usually made retrospectively. In this clinical context, rhythm control with restoration of sinus rhythm is considered crucial to minimize ventricular function damage and allow contractility recovery. However, the presence of a thrombus in the left atrial appendage is a limiting factor, typically requiring anticoagulation until the thrombus resolves, at least three weeks, thus delaying the therapy. Case summary We present a case of 65-year-old man with diagnosis of new-onset acute symptomatic heart failure with severe reduced ejection fraction (LVEF 15%), in the context of a typical tachycardic atrial flutter and concomitant thrombus in the left atrial appendage confirmed by transesophageal echocardiography. We successfully performed a thrombus entrapment procedure by means of percutaneous left atrial appendage closure, which allowed immediate restoration of sinus rhythm through cavotricuspid isthmus ablation. After the institution of the heart failure therapy, titrated up to the maximum tolerated dose, we observed a complete restoration of left ventricular function after six months. Discussion Thrombus entrapment by means of left atrial appendage closure is a valid strategy that enables early cardioversion with arrhythmia ablation and rapid restoration of normal cardiac rhythm in severe heart failure with reduced ejection fraction, even in acute situations and typical atrial flutter.
... Their electrocardiogram rarely shows Q waves or signs of LV hypertrophy, whilst LV diastolic diameter tends not to be excessively dilated with a preserved parietal thickness (echocardiography). 36 On the other hand, patients with the impure type regularly present symptoms typical of HF earlier and more severely and, though clinical recovery may be relatively rapid, that of LVEF is not. 36 As mentioned, multiple rhythm disturbances can cause TCMP (Box 1) but, unfortunately, TCMP does not have any complementary tests or specific diagnostic biomarkers or algorithms that favour its identification. ...
... 36 On the other hand, patients with the impure type regularly present symptoms typical of HF earlier and more severely and, though clinical recovery may be relatively rapid, that of LVEF is not. 36 As mentioned, multiple rhythm disturbances can cause TCMP (Box 1) but, unfortunately, TCMP does not have any complementary tests or specific diagnostic biomarkers or algorithms that favour its identification. 1,2 Therefore, its presence should be suspected in any patient with a deteriorated LVEF and chronic or frequently recurrent tachyarrhythmia. ...
... 6 The usual imaging techniques (echocardiography or cardiac magnetic resonance) reveal the presence of dilated cardiomyopathy with moderate to severe impaired LVEF, absence of myocardial hypertrophy and functional mitral regurgitation. 1,36,37 Holter monitoring for 24 hours (or even longer) may be useful in diagnosing frequent paroxysmal cases of tachycardiomyopathy or in checking for a sustained increase in HR. 1 The main diagnostic challenge is differentiating TCMP from non-ischaemic dilated cardiomyopathy (DCM) 2 and, compared with this, patients with TCMP usually have (at diagnosis) a higher HR and lower LVEF but with greater LVEF recovery during follow-up (after HR normalization). 37 On the other hand, patients with DCM tend to have wider QRS complexes, more frequent late gadolinium enhancement (cardiac magnetic resonance) and more rehospitalizations during follow-up. ...
Article
Full-text available
Tachycardia-induced cardiomyopathy is an entity characterized by reversible dysfunction of the left ventricle, which can be induced by different types of arrhythmia such as atrial fibrillation, atrial flutter, incessant supraventricular tachycardia and ventricular arrhythmia (more frequent causes). Correct identification of the causative arrhythmia and normalization of the heart rate (e.g through medical treatment, electrical cardioversion, ablation) can lead to recovery of left ventricular function. Tachycardia-induced cardiomyopathy should be suspected in patients with tachycardia and left ventricular dysfunction (heart failure setting), especially when there is no history of previous heart disease. Its usual phenotype is that of non-ischaemic/non-valvular dilated cardiomyopathy and it can occur in both children (main cause: permanent junctional reciprocating tachycardia) and adults (main cause: atrial fibrillation). With proper treatment, most cases recover within a few months, though there is a risk of relapse, especially when the causal arrhythmia reappears or its control is lost. This is a narrative review that comprehensively addresses the pathophysiology, clinical manifestations, and therapeutic management of tachycardia-induced cardiomyopathy. This article is part of the Emerging concepts in heart failure management and treatment Special Issue: https://www.drugsincontext.com/special_issues/emerging-concepts-in-heart-failure-management-and-treatment.
... Esto puede acontecer en un corazón estructuralmente sano, siendo la única causa de la disfunción sistólica y se denomina tipo 1. En estos casos el tratamiento de la arritmia normaliza la función ventricular. Se designa como tipo 2 cuando la arritmia agrava un compromiso funcional ventricular de otra etiología y el tratamiento de ella mejora parcialmente la función (6,8) . Recientemente se ha propuesto ampliar esta definición incluyendo también la disfunción auricular (cardiomiopatía atrial) generada por arritmias auriculares y el compromiso funcional ocasionado típicamente por la disincronía ventricular en casos de bloqueo de rama izquierda, estimulación del ápex del ventrículo derecho (situaciones que no abordaremos en este artículo) o extrasistolía ventricular de alta incidencia (9) . ...
... También la duración y persistencia de la arritmia tiene trascendencia. De cualquier manera, existe evidencia de que una taquicardia >100 pm durante más de 15% del tiempo es causa potencial de disfunción ventricular (2,8) . ...
... La clásica pregunta ¿qué es primero, el huevo o la gallina?, debe plantearse siempre cuando esta asociación está clínicamente presente. Si la duda persiste, debe tratarse adecuadamente la arritmia, si es posible en forma definitiva y valorar la respuesta clínica (6)(7)(8)(9)(10) . ...
Article
Full-text available
Cardiac arrhythmias are a frequent and usually not considered etiology of ventricular dysfunction. They could be the single cause or a contributing factor of ventricular function compromise. Catheter ablation is an available resource that brings us the possibility to definitively cure several arrhythmias, confirming the diagnosis of arrhythmia induced cardiomyopathy improving or normalizing ventricular function, and in addition to modify the prognostic. We will mainly discuss atrial fibrillation, the arrhythmia more often associated in practice with heart failure. Also, we will analyze the role of premature ventricular contractions as cause or contributing factor to ventricular dysfunction, usually a controversial topic.
... The key diagnostic criterion of AIC is the detection of a pathological tachycardia or persistent arrhythmia in the presence of an otherwise unexplained LV systolic dysfunction (4). The proof of AIC is to document LV systolic dysfunction in serial measurements after pathological tachycardia or resistant arrhythmia in a patient with normal LV functions prior to onset of the arrhythmia (21). However, this proof is rarely seen in clinical practice. ...
... When AIC cannot be differentiated from dilated CMP with consequent tachycardia, treatments for both problems are necessary (3). The correct diagnosis can only be established after demonstration of the improvement of LV function within a few weeks or months after successful treatment of arrhythmia (21). Table 2 shows diagnostic tests, which can help differentiate AIC from other forms of nonischemic dilated CMP. ...
... However, such recovery may be totally absent. This may be related to more extensive myocardial damage produced by longer periods of tachycardia and/or contribution of underlying heart disease (21,75). Researchers reported that patients with HF with recovered EF have better clinical courses including lower mortality than patients with permanently reduced or permanently preserved EF (76). ...
Article
Full-text available
Background Heart failure (HF) is one of the major causes of mortality and morbidity. The identification of causes of left ventricular (LV) systolic dysfunction is important in terms of initiating causal treatment and improving prognosis. Arrhythmia-induced cardiomyopathy (AIC) is a potentially reversible form of cardiomyopathy (CMP) in which LV dysfunction results from atrial or ventricular arrhythmias (1). It can be resolved by eliminating or effectively treating responsible arrhythmia (2).
... The key diagnostic criterion of AIC is the detection of a pathological tachycardia or persistent arrhythmia in the presence of an otherwise unexplained LV systolic dysfunction (4). The proof of AIC is to document LV systolic dysfunction in serial measurements after pathological tachycardia or resistant arrhythmia in a patient with normal LV functions prior to onset of the arrhythmia (21). However, this proof is rarely seen in clinical practice. ...
... When AIC cannot be differentiated from dilated CMP with consequent tachycardia, treatments for both problems are necessary (3). The correct diagnosis can only be established after demonstration of the improvement of LV function within a few weeks or months after successful treatment of arrhythmia (21). Table 2 shows diagnostic tests, which can help differentiate AIC from other forms of nonischemic dilated CMP. ...
... However, such recovery may be totally absent. This may be related to more extensive myocardial damage produced by longer periods of tachycardia and/or contribution of underlying heart disease (21,75). Researchers reported that patients with HF with recovered EF have better clinical courses including lower mortality than patients with permanently reduced or permanently preserved EF (76). ...
... Consequently, there is severely decreased cardiac output and elevated systemic vascular resistance, as well as considerable LV dilatation and stretching of the mitral valve annulus leading to moderate mitral valve regurgitation [9]. In 1996, Fenelon et al. [10] described two entities of TIC: (a) pure TIC in which tachycardia is the sole pathologic mechanism of LV dysfunction; and (b) an impure TIC in which tachycardia worsens a pre-existing cardiomyopathy developed due to a different cause. ...
... It is not well established why some TIC patients with chronic tachycardia develop ventricular dysfunction while others tolerate and maintain normal systolic function [9]. However, suggested risk factors for the development of TIC may include the type, rate and duration of tachycardia, the age of the patient, any determined underlying cardia disease, medication and co-occurring medical condition [10]. ...
... Prognosis mainly depends on two factors that have been well demonstrated to influence the severity of ventricular dysfunction: (a) the rate of arrhythmia and (b) the duration of the arrhythmia [33,38]. However, recovery is extremely variable, which maybe complete, partial, or even absent [10,[39][40]. ...
... En algunos casos, especialmente e n pacientes pediátricos y jóvenes con tipos específicos de TSV que presentan arritmias de carácter incesante y no paroxísticas, el síntoma de presentación no son las habituales palpitaciones sino síntomas de insuficiencia cardíaca. Estos síntomas están provocados por una disfunción ventricular izquierda secundaria a la taquicardia permanente, entidad que se denomina taquicardiomiopatía (5)(6)(7) No debemos olvidar que frente a estos síntomas relativamente benignos, u n a taquiarritmia, tanto supraventricular como ventricular, puede producir un síncope e incluso ser responsable de una muerte súbita (8). Un paciente por tanto en el que una taquicardia ha producido en alguna ocasión un síncope debe de considerarse como una situación de urgencia médica que precisa un diagnóstico rápido y preciso. ...
... Cualquier cambio en la relación A-V, con persistencia de la taquicardia, prácticamente excluye a las anteriores y es diagnóstica de taquicardia auricular. 7. ECG basal en ritmo sinusal Lógicamente, un ECG basal en el que se observa preexcitación ventricular (WPW) es muy sugestivo de que el mecanismo de la taquicardia sea reentrada por la vía accesoria. ...
Article
Full-text available
El diagnóstico diferencial de las taquiarritmias no es una mera disquisición electrocardiográfica. Aunque el electrocardiograma proporciona en último término el diagnóstico definitivo, los datos clínicos recogidos mediante una anamnesis y exploración física cuidadosa pueden proporcionar información adicional de utilidad. Especial interés tiene para el clínico el diagnóstico certero de una taquicardia con QRS ancho donde la diferenciación entre una taquicardia supraventricular y una taquicardia ventricular es esencial desde el punto de vista de la conducta a seguir. Se revisarán a continuación los principales aspectos tanto clínicos como electrocardiográficos que aportan datos de utilidad en el diagnóstico de una taquiarritmia.
... 7,8 Both coincide with the electrocardiographic characteristics of the PVC of this region, with LBBB patterns that have transition zones in V2-V3 and positive polarity in V6 and DI. There are two previously cases reporting of TA PVCs that were associated with tachycardiomyopathy. 13, 14 The association of fast and irregular ventricular rhythms with higher AB has been established as the main cause of tachycardiomyopathy. 11,12,15,16 There is evidence that an AB greater than 10% may result in LVD1, 8, [16][17][18] however, PVC burden greater than 24% appears to be independently associated with a decreased ejection fraction. 19 In such cases either pharmacological treatment or catheter ablation is necessary. ...
... There are 2 types of AiTCM: type 1, in which arrhythmia is the only cause of tachycardiomyopathy, and left ventricular function returns to normal after successful treatment; type 2 refers to arrhythmic event exacerbates underlying damage, and its treatment results in partial resolution of the tachycardiomyopathy. 11, 16 The treatment with RFA is recommended and has demonstrated high success rates when arrhythmias are associated with ventricular dysfunction or situations with AB > 10%. 15 Regarding anatomy, treatment has been observed as more effective in patients with structurally healthy hearts and origin in the right ventricle, 8-11,20 with a success rate between 80% and 90%. ...
Article
Full-text available
Introduction: Most ventricular arrhythmias are related to structural heart disease. When they occur in anatomically normal hearts are known as idiopathic arrhythmias. The highest percentage of premature ventricular complexes (PVC) is originated in the right ventricular outflow tract. However, less frequent sites have been described, such as the tricuspid annulus. Irregular rhythm along with a high percentage of arrhythmic burden (AB) have an important role in the deterioration of left ventricular function. Objective: To describe the return to normal ventricular function after PVC radiofrequency ablation (RFA). Case study: A 75-year-old man, without relevant history, presented with mild exertion dyspnea and frequent palpitations. The physical examination was normal, the 12-lead electrocardiogram showed premature ventricular contractions with a left bundle branch block (LBBB) pattern and superior axis. A Holter monitoring documented a 35% arrhythmic burden and transthoracic echocardiography demonstrated an LVEF of 40% and global hypokinesia, without valvular heart disease. An electrophysiological study was conducted with three-dimensional mapping that observed the origin of the PVC at the septal tricuspid annulus. RFA was performed in this area, resulting in the immediate disappearance of PVC. Results: At 3 months a 24-hour Holter monitoring showed 0.02% of AB and a transthoracic echocardiogram showed LVEF of 65%. Conclusion: Premature ventricular contractions originating from the tricuspid annulus are an uncommon cause of tachycardiomyopathy and RFA treatment is safe and effective.
... 190 However, when asymptomatic, some patients with very frequent or incessant NSVT may develop TICMP over time. 191 Pending symptoms or alteration in ventricular function, observation with no specific therapy is perfectly acceptable, although follow-up is mandatory. ...
... Tachycardia-induced cardiomyopathy may be divided into two types: (i) pure, where tachycardia is the sole mechanism of worsening of LV function; and (ii) mixed, or impure as it was originally termed, where tachycardia worsens a pre-existing cardiomyopathy due to a different cause. 191 However, the fact that pure TICMP may develop with variable incidence and severity in different patients with a similar fast heart rate over a similar duration raises the question that a latent cardiomyopathy or an underlying myocardial susceptibility could play a role in the development of TICMP. ...
Article
Asymptomatic arrhythmias are frequently encountered in clinical practice. Although studies specifically dedicated to these asymptomatic arrhythmias are lacking, many arrhythmias still require proper diagnostic and prognostic evaluation and treatment to avoid severe consequences, such as stroke or systemic emboli, heart failure, or sudden cardiac death. The present document reviews the evidence, where available, and attempts to reach a consensus, where evidence is insufficient or conflicting.
... It is defined as myocardial dysfunction caused by a rapid ventricular rate that is completely or partially reversible after normalization of the heart rate. 5,6 Our knowledge of APs and TICM in dogs currently is limited. Single case reports and small case series have been reported. ...
... 55,56 Time to onset of ventricular dysfunction also is dependent on other factors, including underlying structural heart disease and patient age. 6 We found no relationship between LV systolic dysfunction and fastest OAVRT cycle length before antiar- Finally, our study confirms the efficacy of RFCA for eliminating APs, thus curing dogs of associated tachyarrhythmias and often totally reversing myocardial dysfunction. The long-term success rate of a single RFCA in the dogs undergoing ablation was 95% (91% success rate when including dogs dying before AP ablation). ...
Article
Full-text available
Background: Atrioventricular accessory pathways (APs) in dogs have been reported rarely. Data regarding clinical presentation and long-term outcome after radiofrequency catheter ablation (RFCA) are limited. Hypothesis/objectives: To study clinical features, electrophysiologic characteristics, and outcome of RFCA in dogs with APs. Animals: Eighty-nine dogs presented consecutively for RFCA of APs. Methods: Case series. Results: Labrador retrievers (47.2% of dogs) and male dogs (67.4% of dogs) were most commonly affected. Labrador retrievers were more likely to be male than non-Labrador breeds (P = .043). Clinical signs were nonspecific and most commonly included lethargy and gastrointestinal signs. Concealed APs were more prevalent in Labrador retrievers than other breeds (P = .001). Right-sided APs (91.7%) predominated over left-sided (8.3%). Tachycardia-induced cardiomyopathy (TICM) occurred in 46.1% of dogs, with complete resolution or substantial improvement noted on one-month postablation echocardiograms. Radiofrequency catheter ablation successfully eliminated AP conduction long term in 98.8% of dogs in which it was performed. Complications occurred in 5/89 dogs. Recurrence in 3 dogs was eliminated long term with a second procedure. Clinical importance/conclusions: Accessory pathways are challenging to recognize in dogs because of nonspecific clinical signs, frequency of concealed APs that show no evidence of their presence during sinus rhythm, and intermittent occurrence of tachyarrhythmias resulting from APs. Tachycardia-induced cardiomyopathy commonly occurs with AP-mediated tachycardias and should be considered in any dog presenting with a dilated cardiomyopathic phenotype because of its good long-term prognosis with rhythm control. Radiofrequency catheter ablation is a highly effective method for eliminating AP conduction and providing long-term resolution.
... Sustained tachycardia leads to abnormal cellular remodeling and a reduction in the number of microtubules within myocardial cells, which may contribute to myocardial contractile dysfunction [21]. Chronic tachycardia may also result in the depletion of high-energy phosphate, leading to decreased intracellular sarcolemmal sodium/potassium ATPase activity and an altered enzyme distribution affecting calcium handling [22]. Consequently, infants and young children may have heightened intracellular calcium stores. ...
Article
Full-text available
Background: Tachycardia-induced cardiomyopathy (TIC) is caused by prolonged tachycardia, leading to left ventricular dilatation and systolic dysfunction with heart failure. Although TIC is more common in adults, it is rare in early infancy. Methods: Clinical testing was performed as part of medical evaluation and management. Next-generation sequencing (NGS) was conducted for a patient with TIC. A literature review on TIC was also conducted. Results: The case involved a 5-month-old infant referred to the hospital due to symptoms of heart failure lasting at least two months. The infant’s heart rate was 200 beats per minute, the left ventricular ejection fraction fell below 14%, and electrocardiograms showed atrial flutter, suggesting TIC. After cardioversion, there was no recurrence of atrial flutter, and cardiac function improved 98 days after tachycardia arrest. The NGS did not identify any pathogenic variants. The literature review identified eight early infantile cases of TIC. However, no previous reports described a case with such a prolonged duration of TIC as ours. Conclusions: This is the first report of a case of prolonged TIC in a child with the documented time to recover normal cardiac function. The improvement of cardiac function depends on the duration of TIC. Early recognition and intervention in TIC are essential to improve outcomes for infantile patients, as timely treatment offers the potential for recovery.
... Sustained tachycardia causes abnormal cellular remodeling and decreases the number of microtubules within myocardial cells, which may contribute to myocardial contractile dysfunction [21]. Chronic tachycardia may also cause depletion of highenergy phosphate, which may lead to decreased intracellular sarcolemmal sodium/potassium ATPase activity and altered enzyme distribution affecting calcium handling [22]. Thus, infants and young children may function more rapidly because of reduced intracellular calcium stores. ...
Preprint
Full-text available
Background: Tachycardia-induced cardiomyopathy (TIC) is caused by prolonged tachycardia leading to left ventricular dilatation and systolic dysfunction with heart failure. Although TIC is more common in adult, it is rare in early infant. Methods: Clinical testing was performed as part of medical evaluation and management. Next gene se-quencing (NGS) was performed for a patient with TIC. Literature review about TIC was con-ducted. Results: The case was a 5-month-old infant referred the hospital due to symptoms with heart failure at least lasting two months. Heart rate was 200 beats per minute, left ventricular ejection fraction fell below 14%, and electrocardiograms showed atrial flutter, suggesting TIC. After cardiover-sion, there was no recurrence of atrial flutter, and cardiac function was improved at 98 days after tachycardia arrest. There were no pathogenic variants identified according to NGS. Literature review identified 8 early infantile cases with TIC reported. However, there were no previous re-ports such as our case with longer duration of TIC. Conclusions: Improvement of cardiac function depends on the duration of TIC. TIC should be considered in all patients with a dilated cardiomyopathy of uncertain origin and who have tachycardias such as atrial flutter.
... Tahikardijom indukovana kardiomiopatija se ne javlja kod svih bolesnika sa dugotrajnim aritmijama već postoje i oni pacijenti koji, i pored brze komorske frekvencije, održavaju normalnu sistolnu funkciju leve komore. Pretpostavljeni faktori rizika za nastanak tahikardiomiopatije su: vrsta aritmije, njeno trajanje i srčana frekvencija, godine života pacijenta, postojanje strukturne bolesti srca i komorbiditeta, kao i upotreba lekova (8,9). ...
Article
Full-text available
Cardiac arrhythmias often coexist with heart failure and can be its cause or consequence. Tachycardia-induced cardiomyopathy most often occurs as a consequence of persistent atrial tachyarrhythmias, such as atrial fibrillation and atrial flutter. Accelerated heart rate leads to systolic and diastolic dysfunction of the left ventricle with its consequent dilation together with changes at the neurohumoral and cellular levels. Clinical presentation varies from asymptomatic tachycardia to end-stage heart failure. Tachycardia-induced cardiomyopathy is an often unrecognized and potentially reversible cause of heart failure. The exact prevalence of tachycardiomyopathy is difficult to determine since the diagnosis is made retrospectively, based on echocardiographically confirmed recovery of the left ventricular function after adequate treatment of the arrhythmia. The most effective treatment is catheter ablation of the arrhythmia. Other treatments include electrical cardioversion, pharmacological rhythm and/ or rate control, and pacemaker implantation with ablation of the atrioventricular node
... CHFimEFin patients with tachycardia-induced cardiomyopathy помимо аритмии. По современным представлениям все случаи ТКМП можно разделить на две подгруппы: «чистые», когда тахикардия является единственным механизмом нарушения функции ЛЖ, и наиболее распространенные «сочетанные», когда существуют другие сопутствующие причины дисфункции ЛЖ [7]. Наличие артериальной гипертензии, гипертрофии ЛЖ, пожилой возраст и дислипидемия, конечный диастолический размер более 5,5 см снижали уверенность в наличии ТКМП у нашего пациента, а также повышали вероятность ишемического генеза ФП и ХСН. ...
Article
Full-text available
Heart failure and arrhythmias are pathogenetically closely interconnected and they are mutually aggravating each other. At the same time, tachycardia-induced cardiomyopathy is particularly a reversible disease with proper treatment. This article presents a case report of an elderly patient with hypertension and atrial fibrillation, which are associated to an advanced heart failure and complicating the management of a decreasing kidneys filtration capacity, hematuria and brain stroke. In this case report, tachycardia-induced cardiomyopathy is caused by persistent atrial fibrillation. A complex approach to diagnosis and evidence-based treatment (in particular cardioversion and radiofrequency ablation) made it possible to restore sinus rhythm and compensate heart failure. Dynamics of the clinical state of the patient, laboratory indicators, echocardiographic characteristics allowed us to retrospectively verify atrial fibrillation-mediated cardiomyopathy as the main cause of heart failure progression, and classify this clinical case as heart failure with improved ejection fraction.
... Por lo general la recuperación clínica es temprana, pero la recuperación de la función sistólica puede tardar desde cuatro semanas hasta seis meses y ser completa o parcial de acuerdo con el tiempo de evolución del trastorno del ritmo (13) . Fenelon propuso los siguientes criterios diagnósticos: dilatación del ventrículo izquierdo con síntomas de falla cardíaca y arritmia crónica o muy frecuente más de 10%-15% del día (6). Se requieren un alto índice de sospecha en pacientes con falla cardíaca y la coexistencia de arritmias. ...
Article
Se presenta el caso de una paciente de sexo femenino de 74 años de edad, con síndrome de falla cardiaca, antecedente de enfermedad coronaria con revascularización percutánea previa y flutter auricular con respuesta ventricular rápida sin adecuado control con betabloqueadores y antiarritmicos, con dilatación progresiva del ventrículo izquierdo, deterioro de la función sistólica y de la fracción de eyección hasta 18%, luego del episodio de arritmia incesante. Se demostró en Se presenta el caso de una mujer de 74 años de edad, con síndrome de falla cardíaca, antecedente de enfermedad coronaria con revascularización percutánea previa y flutter auricular con respuesta ventricular rápida sin adecuado control con betabloqueadores y antiarrítmicos; tenía dilatación progresiva del ventrículo izquierdo, deterioro de la función sistólica y de la fracción de eyección hasta 18%, luego del episodio de arritmia incesante. Se demostró en la angiografía coronaria estenosis moderada a grave de los stents previamente implantados en las arterias descendente anterior y circunfleja, por lo cual se implantaron stents medicados. Posteriormente se hizo cardioversión eléctrica exitosa y cuatro semanas después permanecía en ritmo sinusal con recuperación de la función ventricular, evidenciada por la normalización de la fracción de eyección del ventrículo izquierdo, lo que corroboró la presunción diagnóstica de taquicardiomiopatía.
... Ранее были представлены данные исследований, демонстрирующие, что ТИКМП встречается в любом возрасте, включая детей и подростков, при этом чаще она ре-Таблица 2. Связь между параметрами эхокардиографии и их влиянием на развитие ТИКМП у пациентов с декомпенсацией хронической сердечной недостаточности со сниженной фракцией выброса левого желудочка [27]. В нашем исследовании не было получено достоверных данных о влиянии возраста на развитие ТИКМП. ...
Article
Full-text available
Aim To identify possible predictors of tachycardia-induced cardiomyopathy (TICMP) in patients with newly developed decompensated chronic heart failure (CHF) of nonischemic origin with reduced left ventricular ejection fraction (LV EF) and with persistent atrial tachyarrhythmias. Material and methods This study included 88 patients with newly developed decompensated CHF of nonischemic origin with reduced LV EF and persistent atrial tachyarrhythmias. Resting 12-lead electrocardiography (EGC) and transthoracic echocardiography (EchoCG) were performed upon admission and following the electrical impulse therapy for all patients. Also, 24-h ECG monitoring was performed to confirm sinus rhythm stability. After recovery of sinus rhythm, outpatient monitoring was performed for three months, including repeated EchoCG to evaluate the dynamics of heart chamber dimensions and LV EF. Results The patients were divided into two groups based on the increase in LV EF: 68 responders (TICMP patients with a LV EF increase by >10%) and 20 non-responders (patients with an increase in LV EF by <10% during 3 months following the sinus rhythm recovery). According to results of the baseline EchoCG, LV EF did not significantly differ in the two subgroups (TICMP, 40±8.3 %, 18-50 % and non-responders, 38.55±7.9 %, 24-50 %); moreover, the incidence of cases with LV EF <30% did not differ either (9 patients TICMP and 2 non-responders, р=1.0). TICMP patients compared to non-responders, had significantly smaller left atrial dimensions (4.53±1.14 (2-7) cm and 5.68±1.41 (4-8) cm, р=0.034; 80.8±28.9 (27-215) ml and 117.8±41.3 (46-230) ml, р=0.03, respectively) and left ventricular end-systolic volume (ESV) (67.7±33.1 (29-140) ml and 104.5±44.7 (26-172) ml, р=0.02, respectively). The effect of major EchoCG parameters on the probability of TICMP development was assessed by one-factor and multifactor regression analyses with adjustments for age and sex. The probability of TICMP increased with the following baseline EchoCG parameters: end-diastolic volume (EDV) <174 ml [odd ratio (OR), 0.115, 95 % confidence interval (CI): 0.035-0.371], ESV <127 ml [OR, 0.034, 95 % CI: 0.007-0.181], left atrial volume <96 ml [OR, 0.08 , 95 % CI: 0.023-0.274], right ventricular dimension <4 cm [OR, 0.042 , 95 % CI: 0.005-0.389].Conclusion Among patients with newly developed decompensation of CHF with reduced LV EF of non-ischemic origin and persistent atrial arrhythmias, TICMP was detected in 72 % of patients. The probability of TICMP did not depend on baseline EF and duration of arrhythmias, but increased with the following baseline EchoCG parameters: EDV< 174 ml, ESV< 127 ml, left atrial volume <96 ml, right ventricular dimension <4 cm. The multifactorial analysis showed that a right atrial volume <96 ml is an independent predictor for the development of TICMP.
... It should always be remembered to consider sinus tachycardia. There have been various instances where Episodic SVT has been misdiagnosed as a panic attack or anxiety (7) . This is especially true if the case has had a history of psychiatric ailment(s). ...
Article
Full-text available
Background Supraventricular tachycardia comprises 80% of regular tachycardia that present to the emergency rooms and cardiology clinics. It is of many mechanisms and electrocardiography features. In a high percentage of cases, it occurs in the structurally-normal heart. Epidemiologically it has been discovered that it is more widespread in females than in males. Objectives Electrocardiography (ECG) criteria help differentiate the types of Supraventricular tachycardia (SVT) and predict the underlying mechanism. For example, the patient with short R.P. and long P.R. types is more suggestive of atrioventricular nodal reentrant tachycardia (AVNRT), where ablation therapy is more successful than in atrial tachycardia and atrioventricular reentrant tachycardia (AVRT) Differentiating between AVNRT, AVRT, and atrial tachycardia is extremely significant regarding the acute termination by medications; Adenosine and Calcium-channel blockers (CCBs) are found more effective in atrioventricular reentrant tachycardia, CCBs should be avoided in long R.P. and short P.R. Patients and Methods A retrospective cross-sectional study was conducted between December 2016 and February 2018. This study included patients who visited the emergency room with a narrow-QRS-complex tachycardia. Results Eighty-five patients with regular narrow-QRS-complex tachycardia were included. The mean ± S.D. of the participants-age was 46.29 years ±12.71, 56 cases (65.9%) were females, and 29 (34.1%) were males. The mean ± S.D. of the disease duration of the condition was 5.07±5.52 years, and a frequency of 3.8 attacks per 6 months, and a mean duration of each episode was approximately 80 minutes for each episode. Regarding the symptomatology of tachycardia, almost all patients had symptoms of palpitation, 11.8% had presyncope, and 4.7% had syncope. Conclusion Atrioventricular nodal reentries tachycardia (slow/fast) are the most common in our study. AVRNT was found more prevalent in females than males. Atrioventricular reentry tachycardia was found in males more than females in our study.
... The most important and common of all mechanisms relates to optimal VR control, which seems to be an elusive target. In general, any persistent or chronic tachycardia (incessant supraventricular or ventricular tachycardia or AF) that occurs more than 10-15% of the day may result in TCM [16]. Persistent tachycardia can impair myocardial contractility, either directly via decreased diastolic filling or through alterations in cellular and neurohormonal mechanisms [3]. ...
Article
Full-text available
Many patients with persistent, chronic, or frequently recurring paroxysmal atrial fibrillation (AF) may develop a tachycardiomyopathy (TCM) with left ventricular (LV) dysfunction and heart failure (HF), which is reversible upon restoration and maintenance of sinus rhythm, when feasible, or via better and tighter ventricular rate (VR) control. Mechanisms involved in producing this leading cause of TCM (AF-TCM) include loss of atrial contraction, irregular heart rate, fast VR, neurohumoral activation, and structural myocardial changes. The most important of all mechanisms relates to optimal VR control, which seems to be an elusive target. Uncontrolled AF may also worsen preexisting LV dysfunction and exacerbate HF symptoms. Data, albeit less robust, also point to deleterious effects of slow VRs on LV function. Thus, a J-shaped relationship between VR and clinical outcome has been suggested, with the optimal VR control hovering at ~ 65 bpm, ranging between 60 and 80 bpm; VRs above and below this range may confer higher morbidity and mortality rates. A convergence of recent guidelines is noted towards a stricter rather than a more lenient VR control with target heart rate < 80 bpm at rest and < 110 bpm during moderate exercise which seems to prevent TCM or improve LV function and exercise capacity and relieve TCM-related symptoms and signs. Of course, restoring and maintaining sinus rhythm is always a most desirable target, when feasible, either with drugs or more likely with ablation. All these issues are herein reviewed, current guidelines are discussed and relevant data are tabulated and pictorially illustrated.
... The main approach to treatment of tachycardia-induced cardiomyopathy is control of the tachyarrhythmia. With the elimination of the underlying arrhythmia, the recovery of ventricular function is often seen within days to weeks in infants [10]. ...
Article
Full-text available
b> Background: Arrhythmias in neonates are uncommon and usually affect newborns with a normal heart or associated with structural heart disease. Meanwhile, one uncommon type of supraventricular arrhythmias is atrial flutter (AF), which is reentry mechanisms in the atrium. The AF may result in heart failure or even death, but the majority of its cases have revealed favorable prognosis in the event of early prenatal diagnosis and immediate treatment [J Am Coll Cardiol. 2006;48:1040–6, Semin Fetal Neonatal Med. 2006;11:182–90, and Arch Argent Pediatr. 2007;105:427–35]. A persistent tachyarrhythmia can progress to a state of cardiac dysfunction known as tachycardia-induced cardiomyopathy. While this may be a rare cause of dilated cardiomyopathy and heart failure in children, the condition is usually reversible and should be considered in newborn and infants [Europace. 2011;14(4):466–473]. Case Report: A preterm 33+1-week male newborn with birth weight 2,790 g was delivered through cesarean section. The baby presented with tachycardia after birth associated with respiratory distress. The physical examination showed heart rate >220/min, and ECG showed “saw tooth pattern” after intravenous adenosine boluses confirming diagnosis of AF (2-3:1). The heart rate reverted to sinus rhythm after synchronized cardioversion. Due to poor LV myocardial performance with dilated chambers, the baby received intravenous milrinone, followed by oral captopril. The baby was discharged on oral medications in perfect clinical condition, and follow-up showed no recurrence AF with improved cardiac function. Conclusion: Despite the rare occurrence, AF should be considered in differential diagnosis of newborn arrhythmia and diagnosed after intravenous adenosine injection. In few cases, AF can be associated with dilated cardiomyopathy which is a reversible condition.
... "pure" and "impure" tachycardiomyopathy based on co-existence with or without the basic heart disease. 1 The "pure" tachycardiomyopathy is an uncontrolled tachyarrhythmia in a normal heart, which is the sole pathogenic factor to normal myocardium. It completely recovers after termination of the tachycardia (Reference: PMID: 16951726). ...
... To this day, two categories of the disease have been described: Arrhythmia-induced TCM, where the arrhythmia is the sole reason for the dysfunction, and arrhythmia-mediated TCM, where the arrhythmia can exacerbate or worsen heart failure (HF) or an underlying heart disease [1]. The former can also be referred to as "pure" TCM and the latter as "impure" TCM [7,8]. ...
Article
Full-text available
Tachycardiomyopathy (TCM) is an underestimated cause of reversible left ventricle dysfunction. The aim of this study was to identify the predictors of recurrence and incidence of major cardiovascular events in TCM patients without underlying structural heart disease (pure TCM). The prospective, observational study enrolled all consecutive pure TCM patients. The diagnosis was suspected in patients admitted for heart failure (HF) with a reduced ejection fraction and concomitant persistent arrhythmia. Pure TCM was confirmed after the clinical and echocardiographic recovery during follow-up. From 107 pure TCM patients (9% of all HF admission, the median follow-up 22.6 months), 17 recurred, 51 were hospitalized for cardiovascular reasons, two suffered from thromboembolic events and one died. The diagnosis of obstructive sleep apnoea syndrome (OSAS, hazard ratio (HR) 5.44), brain natriuretic peptide on admission (HR 1.01 for each pg/mL) and the heart rate at discharge (HR 1.05 for each bpm) were all independent predictors of TCM recurrence. The left ventricular ejection fraction at discharge (HR 0.96 for each%) and the heart rate at discharge (HR 1.02 for each bpm) resulted as independent predictors of cardiovascular-related hospitalization. Pure TCM is more common than previously thought and associated with a good long-term survival but recurrences and hospitalizations are frequent. Reversing OSAS and controlling the heart rate could prevent TCM-related complications.
... [27][28][29] Proposed mechanisms of tachycardia-mediated cardiomyopathy include impaired coronary flow reserve, abnormal cardiac calcium handling, myocardial images depletion, extracellular matrix, and myocyte remodeling. 28,30 Conversely, chronic heart failure promotes progression of AF via neuroendocrine, ultrastructural, and microstructural processes. Chronically elevated left atrial pressures in patients with heart failure leads to remodeling and fibrosis of the left atrial architecture, subsequently serving as a substrate for AF. 31 Areas subjected to high atrial stress frequently show left atrial voltage abnormalities in patients with persistent AF. 32 Persistent upregulation of the renin-angiotensin-aldosterone axis also promotes atrial fibrosis. ...
Article
Catheter ablation for atrial fibrillation in patients with heart failure with reduced ejection fraction is associated with improvement in patient-centered outcomes, such as mortality, heart failure readmission, and atrial fibrillation recurrence, compared with standard medical therapy with or without device therapy. The evidence is not as robust in patients with atrial fibrillation and heart failure with preserved ejection fraction.
Chapter
The pharmacological approach to atrial fibrillation (AF) involves heart-rate control, anticoagulation, and restoration of normal sinus rhythm. Whereas there is strong evidence demonstrating a reduction in morbidity and mortality using anticoagulation for AF, there are no large-scale prospective studies demonstrating a similar benefit for using antiarrhythmic drugs to maintain sinus rhythm. This chapter reviews the data regarding anticoagulation, and presents an approach to managing clinical scenarios involving rate-slowing drugs and antiarrhythmic therapy.
Article
Background Arrhythmia-induced Cardiomyopathy (AiCM) represents a subtype of acute heart failure (HF) in the context of sustained arrhythmia. Clear definitions and management recommendations for AiCM are lacking. Purpose The European Heart Rhythm Association Scientific Initiatives Committee (EHRA SIC) conducted a survey to explore the current definitions and management of patients with AiCM among European and non-European electrophysiologists. Methods A 25-item online questionnaire was developed and distributed among EP specialists on the EHRA SIC website and on social media between September 4th and October 5th 2023. Results Of the 206 respondents, 16% were female and 61% were between 30-49 years old. Most of the respondents were EP-Specialists (81%) working at University Hospitals (47%). While most participants (67%) agreed that AiCM should be defined as a left ventricular ejection fraction (LVEF) impairment after new onset of an arrhythmia, only 35% identified a specific LVEF drop to diagnose AiCM with a wide range of values (5-20% LVEF drop). Most respondents considered all available therapies: catheter ablation(93%), electrical cardioversion(83%), antiarrhythmic drugs (76%) and adjuvant HF treatment(76%). 83% of respondents indicated that adjuvant HF treatment should be started at first HF diagnosis prior to antiarrhythmic treatment and 84% agreed it should be stopped within six months after LVEF normalization. Responses for the optimal time point for the first LVEF reassessment during follow-up varied markedly (1 day-6 months after antiarrhythmic treatment). Conclusion This EHRA Survey reveals varying practices regarding AiCM among physicians, highlighting a lack of consensus and heterogenous care of these patients.
Article
Tachycardiomyopathy or tachycardia-induced cardiomyopathy (TIC) is a relatively rare but completely or partially treatable condition, where there is an impairment of left ventricular (LV) function secondary to chronic, continuous, or intermittent tachycardia, which presents as heart failure. It has been shown that the rate control by means such as cardioversion, negative chronotropic agents, and surgical- or catheter-based atrioventricular nodal ablation, depending on the etiology, resulted in significant improvement of systolic function. The diagnosis of TIC is entertained following the observation of improvement in LV systolic function, after necessary therapy to control the arrhythmia or heart rate. It is necessary that the clinicians should have a high index of suspicion while dealing with LV systolic dysfunction or dilated cardiomyopathy and should control the arrhythmia stringently. This case report describes a 14-year-old boy presenting with breathlessness of 18–24-month duration who had features of dilated cardiomyopathy on echocardiography. Impaired LV systolic function was due to fascicular ventricular tachycardia and he recovered completely after catheter-based ablation within a period of 5–6 months.
Article
Tachycardiomyopathy (TMP) is the development of heart failure due to a cardiac arrhythmia – triggered by rapid and/or irregular ventricular actions. TMP is in principle a (at least partially) reversible disease, so that control of the arrhythmia is of central importance. This article provides an overview of the causes, diagnosis and therapy.
Article
Full-text available
Tachycardia-induced cardiomyopathy (TIC) can result in both systolic and/or diastolic ventricular dysfunction as a result of the prolonged fast heart rate which is reversible upon controlling the fast heart rate or arrhythmia. The exact heart rate that can lead to this is not clear, however, a heart rate > 100 in general needs attention. Tachycardia-induced cardiomyopathy is a well-established cause of left ventricular dysfunction which usually happens due to an increased atrial or ventricular rate. The incidence of TIC is very low although the exact incidence is unclear. It should be considered in all patients with dilated cardiomyopathy or those with no obvious explanation for dilated cardiomyopathy and in presence of tachycardia or atrial fibrillation with a rapid ventricular response. Tachycardia-induced cardiomyopathy has also been labeled as arrhythmia-induced cardiomyopathy lately. We present a case of a 50-year-old patient who presented with a fever of 39oC, feeling generally unwell, had a sore throat, and collapsed at home after several episodes of vomiting after two days of intense exercise. He was diagnosed with suspected tonsillitis and was treated with co-amoxiclav. He was exercising over 10 hours weekly for the last two months in the gym for the Ironman triathlon in London. An echocardiogram showed severe left ventricular systolic dysfunction (LVSD) with a left ventricular ejection fraction (LVEF) of 25%. An electrocardiogram showed sinus tachycardia with a right bundle branch block (RBBB). Cardiac magnetic resonance imaging (CMR) showed normal biventricular function with an ejection fraction (EF) of 71% four months later. The patient was diagnosed with tachycardia-induced cardiomyopathy. This case is unique as the patient presented with transient severe LVSD after training for the ironman triathlon and spontaneous recovery.
Article
Full-text available
Isoleucyl‐tRNA synthetase 2 (IARS2) encodes mitochondrial isoleucine‐tRNA synthetase. Pathogenic variants in the IARS2 gene are associated with mitochondrial disease. We report a female with IARS2 compound heterozygous variants, p.Val499Glyfs*14 and p.Arg784Trp who presented with infantile spasms, Leigh disease and Wolff‐Parkinson White (WPW) pattern. This report expands the phenotypic spectrum of IARS2‐related disease. Isoleucyl‐tRNA synthetase 2‐related mitochondrial disease is related to three distinct phenotypes including CAGSSS, isolated cataracts and neurological disorder. Screening for ventricular pre‐excitation (VPE), cardiomyopathy and neuropathy are recommended.
Article
Full-text available
Heart failure (HF) and atrial fibrillation (AF) demonstrate a constantly increasing prevalence during the 21st century worldwide, as a result of the aging population and the successful interventions of the clinical practice in the deterioration of adverse cardiovascular outcomes. HF and AF share common risk factors and pathophysiological mechanisms, creating the base of a constant interrelation. AF impairs systolic and diastolic function, resulting in the increasing incidence of HF, whereas the structural and neurohormonal changes in HF with preserved or reduced ejection fraction increase the possibility of the AF development. The temporal relationship of the development of either condition affects the diagnostic algorithms, the prognosis and the ideal therapeutic strategy that leads to euvolaemia, management of non-cardiovascular comorbidities, control of heart rate or restoration of sinus rate, ventricular synchronization, prevention of sudden death, stroke, embolism, or major bleeding and maintenance of a sustainable quality of life. The indicated treatment for the concomitant HF and AF includes rate or/and rhythm control as well as thromboembolism prophylaxis, while the progress in the understanding of their pathophysiological interdependence and the introduction of the genetic profiling, create new paths in the diagnosis, the prognosis and the prevention of these diseases.
Article
Full-text available
Children with congenital heart disease may cause potential development of glomerulopathyand tubulopathy due to pathophysiological changes related to a structurally abnormal heart andcirculation. Nephrotic range of proteinuria is a rare but important complication. Even children may sufferfrom chronic kidney disease, which has an adverse impact on health outcomes. Unfortunately, very fewstudies addressed this issue . Therefore, it is crucial to consider that patients with congenital heart diseaserepresent renal involvement, take an account, and prevention strategies to reduce negative outcomes. Thisreview aims to discuss the prevalence of renal involvement, diagnosis and treatment of nephropathy inchildren with cyanotic congenital heart disease.Keywords: cyanotic nephropathy, congenital cyanotic heart disease
Article
Full-text available
A 10‐years‐old boy presented with a history of effort intolerance and palpitations for 4 months. His electrocardiogram showed wide complex tachycardia suggestive of fascicular ventricular tachycardia (VT). The echocardiogram showed moderate‐to‐severe left ventricular systolic dysfunction without any structural lesion. The tachycardia was unresponsive to adenosine and direct current cardioversion. It responded to oral verapamil. The electrophysiology study confirmed the tachycardia as left posterior fascicular VT. The tachycardia was successfully ablated guided by Purkinje potential on three‐dimensional mappings. He showed improvement in ventricular functions before discharge. He is doing well on short‐term follow‐up.
Chapter
Full-text available
Arrhythmia-induced cardiomyopathy is a condition where sustained atrial and ventricular arrhythmias as well as ventricular ectopy result in cardiomyopathy and heart failure. Suppression/elimination of culprit arrhythmia results in partial or complete recovery of left ventricular (LV) function. This condition can develop in all age groups, in structurally normal hearts, and in patients with structural heart disease as well. Diagnosing the condition at clinical presentation is challenging and is usually accomplished following recovery of LV function with arrhythmia treatment. Thus, a very high index of suspicion is required for diagnosis. Early and aggressive treatment of culprit arrhythmias, with a focus on curative therapies, is warranted for recovery of LV function and improvement of symptoms. However, ultrastructural changes can persist following myocardial recovery resulting in vulnerability to recurrent arrhythmia and have implications toward long-term prognosis. Several knowledge gaps exist, especially regarding mechanistic understanding, early diagnosis, optimal management strategies, and long-term prognosis, and should guide future research.
Article
Background: The presence of heart failure (HF) has been associated with poorer outcomes in patients undergoing catheter ablation (CA) for atrial fibrillation (AF). However the effectiveness of CA amongst the subset of patients with tachycardia-induced cardiomyopathy (TIC) remains poorly defined. Methods and results: In a retrospective analysis we compared outcomes of first-time CA for persistent AF in a cohort of patients with previously diagnosed TIC (n=45; age 58±8 years; 91% male) to those with structurally normal hearts (non-TIC; n=440; age 55±9 years; 95% male). TIC was defined as impaired ventricular function (LVEF<50%) which was reversed following treatment of HF. We compared atrial arrhythmias (AAs) recurrence after the CA in the TIC and non-TIC cohorts. In the TIC group, LVEF improved from 35.8±8.1 to 57.5±8.3% following treatment of HF. During 3.3±1.5 years follow-up, AAs-free survival following CA was significantly higher in the TIC group as compared to the non-TIC group (69% vs. 42%, p=0.001), despite a comparable CA strategy between the two groups. In multivariable analysis, absence of HF with TIC, longer AF duration and CFAE ablation were independent predictors of arrhythmia recurrence (OR1.02, 95% CI 1.01-1.03, p<0.01, OR 0.40, 95% CI 0.20-0.79, p<0.01 and OR 2.29, 95%CI 1.27-4.11, p<0.01, respectively). In addition, the outcome after the last procedure was superior in the TIC cohort (89% vs. 72%, p=0.03) with fewer CA procedures as compared to the non-TIC cohort (1.3±0.5 vs. 1.5±0.7, p=0.01). Conclusions: Persistent AF patients with TIC have a more favorable outcome after the CA as compared to those without. This article is protected by copyright. All rights reserved.
Chapter
In patients with dilated cardiomyopathy (DCM), it is possible to find a broad range of bradyrhythmias and tachyarrhythmias. Bradyrhythmias and supraventricular arrhythmias can frequently occur in some familial forms such as lamin A/C mutations. Nonsustained ventricular arrhythmias (VA) are observed in about 40% of patients with DCM, but their prognostic role is not clear, and conflicting data have been published in the last 30 years. Multiple mechanisms can explain atrial and ventricular tachyarrhythmias in DCM. Reentry is associated with slow conduction across surviving muscle bundles within regions of interstitial fibrosis, but other mechanisms can be involved, as nonuniform anisotropy of impulse propagation, ion channel dysfunction, and reduced gap junction function.Sudden death (SD) rate has been definitely reduced in the last three decades, but identification of patients at high risk is still a major issue. Despite its limitations, left ventricular (LV) dysfunction is still pivotal for the identification of patients who should be treated with ICD according to current guidelines, while the role of all other invasive and noninvasive parameters is still debated. Cardiac magnetic resonance and possibly genetic analysis, despite not widely available, can be helpful at least in selected cases.Arrhythmias can be the consequence, but also the cause of DCM, in the presence of a sustained heart rate >100/min, after exclusion of other causes of heart failure and if there is a recovery of LV function after achieving arrhythmia control. Finally, pharmacological and non-pharmacological treatment of arrhythmias (in particular ablation) and the role of ICD are discussed.KeywordsAblationAtrial arrhythmiasDilated cardiomyopathyImplantable cardioverter-defibrillatorVentricular arrhythmiasSudden death
Book
This open access book presents a comprehensive overview of dilated cardiomyopathy, providing readers with practical guidelines for its clinical management. The first part of the book analyzes in detail the disease’s pathophysiology, its diagnostic work up as well as the prognostic stratification, and illustrates the role of genetics and gene-environment interaction. The second part presents current and future treatment options, highlighting the importance of long-term and individualized treatments and follow-up. Furthermore, it discusses open issues, such as the apparent healing phenomenon, the early prognosis of arrhythmic events or the use of genetic testing in clinical practice. Offering a multidisciplinary approach for optimizing the clinical management of DCM, this book is an invaluable aid not only for the clinical cardiologists, but for all physicians involved in the care of this challenging disease.
Chapter
Full-text available
Dilated cardiomyopathy is a primary heart disease characterized by progressive dilatation and ventricular dysfunction. Its epidemiology has long been ignored due to lack of universal diagnostic criteria and studies on small samples, often limited to specific geographical areas. Recently, thanks to the first consensus on cardiomyopathies and the advent of the new imaging methods, further information on the epidemiology of this pathology have been identified. Familial screening of relatives of DCM patients highlighted the complex familial inheritance of this disease. Furthermore, the better diagnostic yield provided more accurate data on the real prevalence and incidence of this condition. The development of molecular biology and gene sequencing is opening up to new frontiers in the field of epidemiology, prognosis and genotype and phenotype correlation.
Chapter
Full-text available
Dilated cardiomyopathy (DCM) is defined by the presence of left ventricular (LV) dilation and systolic dysfunction in the absence of abnormal loading conditions or coronary artery disease sufficient to cause the LV systolic impairment. In the last years, advances in pathophysiology, pathology, biomarkers, genetics and molecular medicine, echocardiography, and cardiac magnetic resonance have allowed an evolution from an etiological to a morphological and then to a morphofunctional classification of the disease. Familial forms account for the 40% of cases, and thanks to the recent discoveries in the genetic field, clinicians have the opportunity but also the responsibility to provide an etiological diagnosis, stratify the risk, and treat patients with the best strategy available. Nowadays the etiologic characterization has dramatically improved so that it is possible to understand the etiologic basis of many so-called idiopathic heart muscle disease. A step toward a comprehensive DCM classification and an attempt to reconcile clinic with genetic in the complexity of the disease is genotype-phenotype correlation, with its prognostic implication in clinical practice. In this chapter will be discussed the historical evolution of DCM classification, and an overview of the main issues discussed in the next sections will be given.
Chapter
Full-text available
The last years witnessed an important progress in the diagnosis and treatment of dilated cardiomyopathy (DCM), improving prognosis and life expectancy. However, some important issues in clinical management remain unresolved. The role of genetic testing, the arrhythmic stratification, and the therapeutic approach still represent areas of uncertainty. The way for improving care of DCM should go through better understanding of the etiological basis of the disease, appropriate risk stratification, and development of new therapies. The abovementioned issues represent the most important and demanding challenges for the next future research on DCM.
Chapter
Full-text available
Dilated cardiomyopathy is characterized by progressive cardiomyocyte loss leading to ventricle dilation and dysfunction. Over the last decade, multiple evidence has shown that treatment of this condition might be attempted through the administration of either cells of various derivations or nucleic acids. In the case of cell therapy, there is ample consensus that no stem cells can directly regenerate the myocardium; however some cell types could provide benefit through a paracrine function on resident cardiomyocytes. Various nucleic acids, including microRNAs and antisense locked nucleic acids targeting microRNAs and long non-coding RNAs, can stimulate regeneration by promoting the proliferation potential of endogenous cardiomyocytes. Albeit at the preclinical phase, these approaches hold a great promise for the development of innovative therapeutics.
Chapter
Full-text available
Cardiovascular imaging is key for the assessment of patients with heart failure. Today, both cardiac magnetic resonance and cardiac computed tomography play an established role in the assessment of patients with suspected and confirmed heart failure syndromes. In particular, cardiac magnetic resonance is of paramount importance in identifying etiology of left ventricular dysfunction. It has an increasing role in prognostic stratification and in clinical decision-making around therapy. Key strengths include its ability to characterize myocardial tissue, unrestricted field of view, lack of radiation, as well as accuracy and reproducibility.
Chapter
In the last decades, long-term survival of patients affected by dilated cardiomyopathy (DCM) has been markedly improved. The main milestones, such as the early diagnosis and the systematic follow-up, the proper etiological characterization at the onset of the disease, and a multidisciplinary approach to the patients together with the optimal medical and device treatment and the rigorous tailored follow-up, accompanied these prognostic improvements. However, DCM still remains the most common cause of heart transplantation and one of the leading causes of cardiac death in the western world. Therefore, proper prognostic stratification and systematic follow-up are the cornerstones to optimize medical management and improve outcomes of patients with DCM.
Chapter
Full-text available
Endomyocardial biopsy (EMB) is a useful diagnostic tool for the investigation and treatment of myocardial diseases. An extensive use of EMBs is impossible because this technique is invariably characterized by a mild, but not negligible, rate of major complications (around 1%) even when performed by experienced operators. For these reasons, it is fundamental a correct selection of patients to undergo EMB. In addition to some particular clinical contexts (after heart transplantation or for specific myocardial diseases), the most frequent indication for EMB is the in-depth evaluation of high-risk major clinical syndromes not responding to standard optimized medical therapy in the short term (recent-onset heart failure with relevant left ventricular dysfunction, sustained ventricular arrhythmias). Furthermore, the in-depth characterization of the myocardial substrate with immunohistochemical and biomolecular PCR (polymerase chain reaction) analyses can provide the guide for a biopsy-driven therapeutic plan.
Chapter
Full-text available
Dilated cardiomyopathy (DCM) represents the third most common cause of heart failure (HF) and the most frequent cause of heart transplantation in the western world. DCM aetiologies can be classified as genetic or nongenetic. Genetic causes account for 30–40% of DCMs and involve genes that encode cytoskeletal, sarcomere, and nuclear envelope proteins among others. Transmission is variable but mostly with an autosomal dominant pattern. Acquired causes include myocarditis, tachyarrhythmias, alcohol abuse, drugs, catecholamines, toxins, and metabolic or endocrine disturbances. Before diagnosing DCM, it is necessary to exclude conditions with phenotypic overlap. A comprehensive integrated approach to patients with a newly diagnosed DCM is essential in order to achieve an accurate early prognostic stratification. Thus, the aim of this chapter is to discuss about the clinical features, the natural history, and the spectrum of such a heterogeneous disease.
Chapter
Full-text available
Dilated cardiomyopathy (DCM) is a heart muscle disease characterized by left ventricular or biventricular dilatation or systolic dysfunction without either pressure or volume overload or coronary artery disease sufficient to explain the dysfunction. It is pivotal to exclude possible removable causes of left ventricular dysfunction because this has prognostic implications. A comprehensive integrated approach, including third-level diagnostic tools, should be systematically implemented in clinical practice to remove every possible reversible cause through specific therapeutic interventions. This issue appears essential to promote left ventricular reverse remodeling and subsequent outcome improvement. Thus, the clinical approach to a suspected DCM requires a step-by-step work-up. In this chapter, we dissect the “red flags approach” to DCM with particular focus on easily missed diagnosis.
Chapter
The hallmark pathophysiologic feature of dilated cardiomyopathy is systolic dysfunction. Several pathogenetic mechanisms appear to be operative. These include increased hemodynamic overload, ventricular remodeling, excessive neurohumoral stimulation, abnormal myocyte calcium cycling, excessive or inadequate proliferation of the extracellular matrix, accelerated apoptosis, and genetic mutations. Although beneficial in the early stages of heart failure, these compensatory mechanisms eventually lead to a vicious cycle of worsening heart failure.Genetic causes account for 30–40% of DCM and involve genes that encode a heterogeneous group of molecules that participate in force generation, force transmission, sarcomere integrity, cytoskeletal and nuclear architecture, electrolyte homeostasis, mitochondrial function, and transcription.Additional research will improve our understanding of the complex and longitudinal molecular changes that lead from gene mutation to clinical expression.KeywordsDilated cardiomyopathyPathophysiologyHeart failureLeft ventricular remodelingMolecular etiologyGenetics
Chapter
Full-text available
The prevalence of heart failure (HF) is escalating rapidly, consuming significant healthcare resources, inflicts significant morbidity and mortality, and greatly impacts quality of life. Dilated cardiomyopathy (DCM) is a frequent cause of HF and is characterized by a progressive course. Nowadays pharmacological and non-pharmacological therapies have dramatically changed DCM’s natural history. Familial screening program represents the first step in order to identify preclinic manifestation of DCM: first-degree relatives carrying a disease-causing mutation or without a clear genetic background must perform a periodic clinical and instrumental evaluation. Patients with a clinical diagnosis of HF and LV dysfunction should receive recommended therapies: beta-blockers (BB), ACE inhibitors (ACEi) or angiotensin receptor blockers (ARB), aldosterone antagonists, and more recently angiotensin receptor-neprilysin inhibitor (ARNI) and ivabradine are established therapies for chronic HF. In case of persistent systolic dysfunction and/or severe intraventricular conduction delay, an ICD and/or CRT are indicated. Finally, heart transplantation and mechanical circulatory support (MCS) are options that can be used in critically ill HF who can’t be stabilized by medical therapy alone.
Chapter
Full-text available
Echocardiography has crucial importance in the diagnosis of dilated cardiomyopathy (DCM). Echocardiographic features of DCM are left ventricular (LV) dilation and systolic dysfunction with impaired global contractility and normal LV wall thickness and LV diastolic dysfunction with elevation in LV filling pressure. Other frequent characteristics are LV dyssynchrony, right ventricular (RV) dysfunction, atrial dilation, functional mitral and tricuspid regurgitation, and secondary pulmonary hypertension. New echocardiographic technologies can be helpful, i.e., three-dimensional (3D) echocardiography for more accurate assessment of LV volumes and ejection fraction (EF) and speckle tracking for analysis of strain particularly for early diagnosis. Of note, many echocardiographic parameters have demonstrated important prognostic value in DCM.
Article
Takotsubo cardiomyopathy (TC) is characterized by transient wall motion abnormalities most commonly involving the left ventricle (LV). Although biventricular TC had been considered uncommon condition, recently biventricular TC has been reported as a new variant observed in 19–42% of all TC presentations. Since biventricular TC has a poor prognosis as compared with isolated TC, it is important to distinguish between isolated LV TC and biventricular TC. We present a case of 70-year-old female with dyspnea persisting for 2 days. Electrocardiogram showed symmetrical T-wave inversion in leads V2–V4. Transthoracic echocardiography (TTE) revealed diffuse hypo-kinesis except for the apical inferior LV and LV ejection fraction of 32%. Hyper-kinesis of the right ventricular (RV) basal segment and dys-kinesis of the RV apical segment. 2 weeks after admission, coronary angiography showed no evidence of significant stenosis. LV ejection fraction improved to 51% and wall motion abnormalities of the RV basal and apical segments were ameliorated to normo-kinesis. Electrocardiogram revealed symmetrical and deepened T-wave inversion in leads V2–V3. The presence of a transient abnormality in biventricular wall motion beyond a single coronary artery perfusion territory with new electrocardiographic change met the diagnostic criteria of definite TC defined by Mayo Clinic criteria. 4 weeks after admission, no recurrence of wall motion abnormalities in both ventricles were found and T-wave inversion ameliorated. To our knowledge, this is the first report of biventricular TC with asymmetrical abnormities of wall motion between LV and RV.
Article
Background: Catheter ablation of atrial fibrillation (AF) improves left ventricular (LV) function in patients with LV systolic dysfunction, suggestive of underlying arrhythmia-induced adverse remodeling. Objectives: To evaluate whether arrhythmia-induced LV remodeling already occurs in patients with AF and preserved LV systolic function and to assess whether this remodeling is reversible following the restoration of sinus rhythm by catheter ablation. Methods: Forty-three AF patients with preserved LV systolic function (LV ejection fraction 62±7%) underwent cardiovascular magnetic resonance (CMR) before catheter ablation including native T1 mapping using a Modified Look-Locker Inversion recovery (MOLLI) sequence. Twenty-five patients underwent follow-up CMR three months after catheter ablation. Twenty-two matched controls without AF underwent the same CMR protocol. Results: Patients with AF had higher baseline LV native T1 values than controls (1296±55 ms vs. 1243±55 ms; p <0.01). During a median follow-up of 9 months, 17 patients (40%) experienced AF recurrence. No differences in baseline T1 values were observed between patients with and without AF recurrence. There was a significant decrease in native T1 values in patients with successful restoration of sinus rhythm after catheter ablation at 3-months follow-up CMR (1300±45 ms vs. 1270±55; p<0.01) while unchanged in patients with AF recurrence (1303±51 ms vs. 1309±31; p = 0.64). Conclusion: These preliminary results suggest that subclinical arrhythmia-induced LV structural remodeling occurs in AF patients with preserved LV systolic function. This remodeling might be reversible following catheter ablation with successful restoration of sinus rhythm as quantified non-invasively and gadolinium-free by CMR native T1 mapping.
Article
Full-text available
LR was a patient, followed over a 16-year period, who presented with an atrial tachycardia which was initially intermittent, but became incessant. Neither the atrial tachycardia nor the associated rapid ventricular response rate could be treated successfully with available drug therapy, resulting in a dilated cardiomyopathy and New York Heart Association (NYHA) class III-IV congestive heart failure. Acute induction of atrial fibrillation with rapid atrial pacing demonstrated that the associated ventricular rate could be satisfactorily slowed with digitalis therapy. Initially, short bursts from an implanted, radiofrequency controlled, patient activated pacemaker programmed to a rate of 600 bpm and connected to a permanent endocardial atrial J lead successfully interrupted the tachycardia and precipitated atrial fibrillation. Over a period of 3 months, this therapy changed the patient's heart failure to NYHA class II status. Subsequently, precipitation of atrial fibrillation with this technique failed, resulting in return to NYHA class III-IV congestive heart failure. Therefore, a custom-designed, high rate, rate-programmabie pacemaker was implanted to pace the atria rapidly and continuously to maintain atrial fibrillation. A pacing rate of 375 bpm plus digoxin slowed the ventricular rate to 70–80 bpm, with stabilization of the congestive heart failure to NYHA class II. The pacemaker generator was replaced 6 months later, and after another 5 months, pacing was discontinued. The patient's subsequent rhythm remained stable atrial fibrillation with clinically successful control of both the ventricular rate and heart failure (NYHA class II) until the patient's death 72 months later. This unique case demonstrates another form of chronic therapy which, in selected cases, can be used for the long term control of rapid ventricular response rates to supraventricular arrhythmia.
Article
Patients with atrial fibrillation or atrial flutter (AF) are candidates for radiofrequency (RF) catheter ablation of the atrioventricular (AV) node with the aim being to control heart rate. As patients wilh AF can have markedly impaired ventricular function, information concerning the hemodynamic effects of AV node ablation using RF current would be valuable. Fourteen consecutive patients (mean age 65 ± 3 years) with drug-resistant AF underwent AV node catheter ablation with RF current and had permanent pacemaker implantation. The mean left ventricular ejection fraction (FFJ by two-dimensional echoeardiography immediately before ablation was 42 ± 3% (range 14%–54%) and their mean exercise time was 4.4 ± 0.4 minutes. Complete AV block was achieved in all 14 patients with 6 ± 2 RF applications (range 1–18). There was no evidence of any acute cardiodepressant effect associated with delivery of RF current, and EF 3 days after ablation was 44 ± 4%. By 6 weeks after ablation, the left ventricular EF was significantly improved compared to baseline (47 ± 4% postablation vs 42 ± 3% preahlation; P < 0.05), and this modest increase in EF was accompanied by an improvement in exercise time (5.4 ± 0.4 min). In conclusion, delivery of RF current for AV node catheter ablation in patients with AF and reduced ventricular function is not associated with any acute cardiodepressant effect. On the contrary, improved control of rapid heart rate following successful AV node ablation is associated with a modest and progressive improvement in cardiac performance.
Article
Na+,K+-ATPase is a major determinant of myocyte homeostasis and excitation-contraction. Cardiac glycosides such as digitalis and ouabain increase the inotropic state of the heart through the inhibition of Na+,K+-ATPase. While cardiac glycosides are commonly used in the setting of congestive heart failure, optimal therapy would depend upon an intact Na+,K+-ATPase system. Changes in Na+,K+-ATPase activity and glycoside receptor density with the development of cardiomyopathy have not been well defined. Accordingly, left ventricular (LV) function and Na+,K+-ATPase activity and glycoside binding were examined in 7 pigs with dilated cardiomyopathy and in 7 controls. Dilated cardiomyopathy was produced by pacing induced supraventricular tachycardia (SVT) for 3 weeks at 240 bpm. Left ventricular function was examined by simultaneous echocardiography and catheterization. Left ventricular fractional shortening significantly decreased with SVT (34 ± 2 vs. 10 ± 2%, P<0.05) and LV diastolic dimension and pressure significantly increased (3.8 ± 0.3 vs. 5.1 ± 0.4 cm, and 8 ± 2 vs. 27 ± 2 mmHg, respectively, P<0.05) as compared to controls. Na+,K+-ATPase activity was assayed as potassium dependent p-nitrophenol-phosphatase activity. Glycoside receptor density (Bmax) and affinity (KD) was determined using [3H]-ouabain binding assays. Na+,K+-ATPase activity, Bmax, and KD all significantly fell from control values with SVT induced cardiomyopathy (0.64 ± 0.06 vs. 0.45 ± 0.12 μg pNP/mg/h, 5.5 ± 0.4 vs. 1.9 ± 0.4 pmol/mg, and 15 ± 3 vs. 9 ± 3 nm, respectively, P<0.05). The distribution of Na+,K+-ATPase in LV sections taken from control and SVT hearts were examined using immunohistochemical techniques. A patchy distribution of Na+,K+-ATPase along the sarcolemma in SVT sections was observed as opposed to a more uniform distribution in control myocytes. There was no observable change in the relative content and distribution of the Na+,K+-ATPase isoforms α2 and α3 in the SVT sections as compared to controls. In an additional set of experiments, changes in LV as well as isolated myocyte responsiveness to ouabain were examined. Left ventricular fractional shortening and peak were measured following administration of 20–60 μg/Kg of ouabain in control (n = 3) and SVT (n = 3) pigs. In the control group, 40 μg/Kg caused a 25% in LV fractional shortening and a 60% increase in peak from baseline. Cumulative doses of 60 μg/Kg in the control pigs resulted in over a 75% increase in peak from baseline values. Administration of 40 μg/Kg of ouabain produced only a 16% and 20% increase in LV fractional shortening and peak in the SVT group respectively; both significantly lower than controls (P<0.05). In contrast to controls, cumulative doses of 60 μg/Kg in the SVT group were not tolerated and resulted in irreversible ventricular fibrillation. Myocyte contractile responsiveness to cumulative doses of ouabain (0.05–8 μm) was examined in cardiocytes isolated from 3 additional control and SVT hearts. In control myocytes, 2 μm ouabain produced over a 50% increase and 4 μm caused over a 100% increase in velocity of shortening from baseline values. In contrast, there was no significant increase in the velocity of shortening of SVT myocytes at any ouabain concentration.In summary, SVT induced cardiomyopathy caused a reduction in glycoside receptor density and Na+,K+-ATPase activity. These changes were associated with an attenuated LV and myocyte responsiveness to ouabain as well as increased sensitivity to the toxic effects of this cardiac glycoside. These changes in Na+,K+-ATPase activity and glycoside responsiveness may have important implications in the treatment of dilated cardiomyopathies.
Article
The selective infusion of ethanol into the coronary circulation supplying the site of origin of incessant ventricular tachycardia has been demonstrated to abolish this arrhythmia in selected patients. The present study was designed to evaluate the efficacy and safety of the intracoronary ethanol ablation technique in patients with paroxysmal ventricular tachycardia related to prior myocardial infarction. Twenty-three patients with sustained monomorphic ventricular tachycardia that was refractory to conventional antiarrhythmic drug therapy were prospectively studied.
Article
Chronic tachycardia-induced dilated cardiomyopathy causes increased plasma catecholamines and alterations in β-adrenergic responsiveness in vivo. However, whether isolated myocyte contractile response to β-stimulation is directly affected by the development of cardiomyopathy and how these changes are related to alterations in the β-adrenergic receptor system remain unclear. Accordingly, isolated mycoyte function and β-adrenergic responsiveness were examined in two groups of 12 pigs each: sham controls, and with supraventricular tachycardia induced cardiomyopathy (SVT; pace: 240 beats/min, 3 weeks). Isolated LV myocyte percent and velocity of shortening were examined at baseline, with isoproterenol (2-100 nM), and forskolin (0.1-4 μM). Baseline percent and velocity of shortening were significantly reduced with SVT compared to controls (1.6 ± 0.1 vs 5.4 ± 0.2%, 56 ± 3 vs 25 ± 1 μm/s, respectively, P < 0.05). The maximal increase in the percent and velocity of shortening with isoproterenol was significantly blunted in the SVT myocytes compared with controls (3.2 ± 0.4 vs 9.7 ± 1.0%, 48.0 ± 5.3 vs 122.6 ± 15.5 μm/s, respectively, P < 0.05). Similarly, maximal increase in the percent and velocity of shortening with forskolin were reduced with SVT compared to controls (3.3 ± 0.4 vs 10.5 ± 0.6%, 50.7 ± 6.4 vs 120.1 ± 9.7 μm/s, respectively, P < 0.05). In order to determine the cellular basis for these changes in β-adrenergic response, myocytes structure, sarcolemmal β-receptor density and affinity, and adenylate cyclase activity were examined. There was a 25% reduction in β-receptor number with SVT (P < 0.05) but no change in affinity. Basal adenylate cyclase activity was lower with SVT compared to control (46 ± 3 vs 77 ± 10 pmol cyclic AMP/mg/min, P < 0.05), and exhibited a blunted response with both isoproterenol (1mM; 106 ± 19 vs 203 ± 26 pmol cyclic AMP/mg/min, P < 0.05) and forskolin (100 μM; 209 ± 35 vs 378 ± 58 pmol cyclic AMP/mg/min, P < 0.05). Finally, myofibrillar content within SVT myocytes was significantly reduced from controls (43 ± 7 vs 63 ± 4%, P < 0.05). In summary, the cellular basis for the depressed myocyte contractile response to β stimulation with tachycardia induced SVT are probably due to several factors which include: decreased expression of β-receptors, alterations in β-receptor transduction, reduced adenylate cyclase activity, and decreased myocyte contractile protein content.
Article
A 32-year-old black man presented with a history of palpitations since childhood and two syncopal episodes. He was found to have incessant ventricular tachycardia, impaired left ventricular contraction (ejection fraction 9%), and nonobstructive hypertrophic cardiomyopathy. Procainamide abolished the arrhythmia and the ejection fraction rose to 22% in sinus rhythm. Later treatment was switched to amiodarone, which suppressed the ventricular tachycardia but necessitated pacemaker implantation. He has remained well during the subsequent 2 years. Left ventricular ejection fraction has increased to 47% measured in paced rhythm. The improvement in left ventricular function has been attributed to suppression of the incessant ventricular tachycardia.
Article
The contributions of changes in primary systolic and diastolic properties, limitations of contractile reserve, and alterations in energy efficiency to the left ventricular dysfunction seen with chronic pacing tachycardia were investigated. Seven dogs (heart failure group) were ventricularly paced at 250 beats per minute for 26.3 +/- 2.9 days and compared with a separate control group (n = 8). STudies were performed with isolated, metabolically supported hearts coupled to a computer-controlled loading system. Pressure-volume relations and myocardial oxygen consumption (MVO2) were measured to assess chamber systolic and diastolic properties and efficiency (relation between MVO2 and pressure-volume area [PVA]). Systolic function was reduced in failure hearts versus controls as assessed by the slope of the end-systolic pressure-volume relation (1.29 +/- 0.94 versus 2.71 +/- 0.98 mm Hg/ml, p less than 0.01) and lowered end-systolic stiffness at a matched stress (956.1 +/- 123.5 versus 1,401.7 +/- 431.7 g/cm2, p less than 0.05). Diastolic chamber and myocardial stiffness were unaltered in failure hearts, but the unstressed diastolic-arrested volume was significantly larger (33.3 +/- 3.9 versus 21.9 +/- 7.6 ml, p less than 0.01). Inotropic response to increased heart rate and exogenous beta-adrenergic stimulation (dobutamine HCl) was significantly impaired in failure compared with control hearts. Most interestingly, failure hearts had a lowered slope of the MVO2-PVA relation (2.1 +/- 1.1 versus 2.9 +/- 1.4 ml O2.mm Hg-1.ml-1.100 g left ventricle-1, p less than 0.001), indicating increased efficiency of chemomechanical energy conversion. The y intercept of the MVO2-PVA relation, which reflects oxygen costs of basal metabolism and excitation-contraction coupling, was unchanged in the two groups despite decreased contractility of the heart failure hearts. These results demonstrate reduced chamber and myocardial contractility, dilatation without alteration of passive myocardial properties, impaired contractile reserve, and novel alterations in cardiac efficiency in this model of heart failure.
Article
Chronic supraventricular (or ventricular) tachycardia causes a dilated cardiomyopathy. Effective treatment requires ablation of the tachycardia using antiarrhythmic agents, cryoablation, electroablation, or surgical interruption/excision. However, the underlying pathophysiologic mechanisms responsible for the development of supraventricular tachycardia-induced cardiomyopathy have not been fully identified. We hypothesized that chronic supraventricular tachycardia is associated with significant changes in the beta-adrenergic system that may have implications for the pathophysiology and treatment of supraventricular tachycardia-induced cardiomyopathy. Accordingly, we examined the relationship between left ventricular function, plasma norepinephrine level, beta-receptor number and affinity, and response to a beta-agonist (isoproterenol) infusion in eight control pigs and eight pigs subjected to supraventricular pacing-induced tachycardia (240 beats/min for 3 weeks). Left ventricular function was measured using simultaneous echocardiography and catheterization. Left ventricular end-diastolic dimension and pressure increased in pigs with supraventricular tachycardia (5.1 +/- 0.4 cm and 27 +/- 2 mm Hg) versus control pigs (3.8 +/- 0.3 cm and 8 +/- 2 mm Hg), p < 0.05. Left ventricular fractional shortening decreased in supraventricular tachycardia (10 +/- 1%) versus control pigs (34 +/- 1%), p < 0.05. In addition, in the pigs with supraventricular tachycardia the fractional shortening versus left ventricular end-systolic stress relationship fell below the control relationship. Plasma norepinephrine level (measured by high-performance liquid chromatography) increased in pigs with supraventricular tachycardia (3592 +/- 1606 pg/ml plasma) versus control pigs (323 +/- 74 pg/ml plasma), p < 0.05. beta-Receptor number and affinity (measured by [3H]dihydroalprenolol binding) did not change in supraventricular tachycardia (98.6 +/- 11.5 fmol/mg protein and 7.2 +/- 1.1 nmol) versus control pigs (99.1 +/- 9.4 fmol/mg protein and 6.8 +/- 0.5 nmol). The response to isoproterenol infusion (10 micrograms/kg) in supraventricular tachycardia was blunted: the absolute increase in left ventricular peak (+)dP/dt was reduced in supraventricular tachycardia (833 +/- 233 mm Hg/sec) versus control pigs (2180 +/- 139 mm Hg/sec), p < 0.05. Chronic supraventricular tachycardia caused a decreased contractile state, increased plasma norepinephrine level, and caused no change in beta-receptor number or affinity; however, the response to beta-agonist infusion was blunted. These results suggest that chronic supraventricular tachycardia is associated with uncoupling of the beta-receptor from subsequent intracellular components of the beta-adrenergic system. Therefore medical management of chronic supraventricular tachycardia-induced cardiomyopathy before and immediately after definitive ablation may require use of pharmacologic agents whose actions do not depend on an intact beta-adrenergic pathway.
Article
Incessant, rapid, supraventricular tachycardia may be complicated by cardiac failure with ventricular dilatation and hypokinetic wall motion on echocardiography: so-called tachycardia-induced cardiomyopathy. The diagnosis is simple when the cardiac rhythm is not sinus rhythm. The authors report the cases of 4 children aged 7 months to 12 years, referred for diagnosis and treatment of apparently primary cardiomyopathy. The findings of spontaneous or vagally-induced atrioventricular conduction defects, a permanently rapid atrial rhythm though influenced by 24 hour variations, or periodic abnormal rate increases, suggested myocardial dysfunction due to an ectopic atrial tachycardia. This was an essential step in management as the control of the tachycardia by amiodarone or betablocker therapy resulted in regression of symptoms and normalisation of left ventricular function. However, some atrial tachycardias are very resistant to medical treatment and, in such cases, there should be no hesitation in using more radical approaches, surgery or ablation, even and especially in patients with severe cardiac failure. In conclusion, apparently primary dilated cardiomyopathy in children may be due to chronic atrial arrhythmia and it is essential to perform at least Holter monitoring in order not to miss this diagnosis.
Article
To assess the potential improvement in left ventricular ejection fraction after cardioversion of chronic atrial fibrillation to sinus rhythm in idiopathic dilated cardiomyopathy, we studied prospectively 17 patients, aged 58 ±6 years, by radionuclide angiocardiography at rest. Left ventricular ejection fraction was determined before treatment and at a mean delay of 4·7 months after eardioversion. Return to sinus rhythm was obtained in 12 patients, pharmacologically or by electrical eardioversion. Five patients remained in atrial fibrillation. No clinical, echocardiographic or haemodynamic finding could predict the success of eardioversion. In chronic atrial fibrillation, the ejection fraction did not change significantly: 30·0 ± 9·1% (19 to 44%) at the first evaluation and 29·5±8·3% (22 to 41%) after 4·7 months. After successful eardioversion, left ventricular ejection fraction improved from 32·1 ± 5·3% (24 to 41%) to 52·9 ± 9· 7% (37 to 71%) (P<0·001). The difference was 20·8±l 1·3% and left ventricular ejection fraction was normalized in 50% (6/12) of the patients. There was a significant reduction in the cardiothoracic ratio on chest X-rays and of the left ventricular end-diastolic diameter on echocardiography; fractional shortening increased (27·7 ±4·3% vs 20· 3 ± 2·7%, P <0·01). A third evaluation was realized after a mean delay of 11·7 months in the patients with successful eardioversion. Sinus rhvthm was present in 83% (10/12) of the patients: seven patients were reevaluated by radionuclide angiography. The improvement in left ventricular function observed at the 4·7 months evaluation was still present. In two patients with recurrence of atrial fibrillation, there was a severe deterioration of left ventricular systolic function. We conclude that, in idiopathic dilated cardiomyopathy, left ventricular ejection fraction can be increased substantially after eardioversion of chronic atrial fibrillation to sinus rhythm.
Article
The purpose of this study was to examine the effects of supraventricular pacing tachycardia on left ventricular function and myocardial structure in newborn, immature pigs and to determine whether immature pigs respond to supraventricular tachycardia differently from adults. Previous studies have shown that supraventricular tachycardia causes dilated cardiomyopathy in adult animals; however, in humans, supraventricular tachycardia-induced congestive heart failure occurs most frequently in children and newborns. Because some clinical diseases may cause myocardial failure in adults but rarely do so in children, it was hypothesized that the effects of supraventricular tachycardia in newborns may be different from those in adults. In two groups of newborn swine (3 weeks of age), left ventricular volume, mass and function were assessed with simultaneous echocardiography and cardiac catheterization and myocardial structure was examined with light and electron microscopy. Six piglets underwent 3 weeks of left atrial pacing tachycardia (240 beats/min) and six littermates served as a control group. Both groups were followed up for 3 weeks. At the end of the protocol, left ventricular dimensions increased in the piglets with supraventricular tachycardia compared with values in the control group, but there were no differences in left ventricular mass. Systolic function, assessed by fractional shortening, peak ejection rate and maximal rate of pressure development, was decreased in the group with supraventricular tachycardia. The fractional shortening-end-systolic stress relation in the piglets with supraventricular tachycardia decreased below normal values. Left ventricular diastolic function assessed by the relaxation time constant was prolonged, the peak filling rate was decreased and left ventricular stiffness was increased in the supraventricular tachycardia group. The morphologic data demonstrated that supraventricular tachycardia did not change total myocyte volume but did decrease total myofibrillar volume. Supraventricular tachycardia caused dilated cardiomyopathy in immature pigs. These changes in left ventricular function were associated with a decrease in cellular contractile proteins. Thus, the effects of supraventricular tachycardia on left ventricular function and structure in immature animals were comparable to previous findings in mature animals.
Article
Fourteen patients (mean age, 48 +/- 19 years) with left ventricular dysfunction in the absence of underlying organic heart disease underwent catheter ablation (nine with direct-current energy and five with radiofrequency energy) to treat drug-refractory, symptomatic supraventricular reentrant tachycardia (mean duration of tachycardia, 22 +/- 17 years). Clinical tachycardias were accessory pathway-mediated tachyarrhythmia (12 patients) and atrioventricular nodal reentrant tachycardia (two patients). Changes of ventricular function after successful ablation, as assessed by radionuclide ventriculography and echocardiography, showed a decrease in left ventricular end-systolic dimension (39 +/- 6 mm to 34 +/- 6 mm; 32 +/- 6 mm; p < 0.05) and in left ventricular end-diastolic dimension (55 +/- 5 mm to 52 +/- 3 mm; 51 +/- 3 mm; p < 0.05) in the early (2 to 3 months) and late (6 to 8 months) follow-up periods, increase of nuclear ejection fraction (38% +/- 8% to 46% +/- 7%; p < 0.05) and fractional shortening (28% +/- 7% to 36% +/- 8%; p < 0.05) in the late follow-up period. Increase of fractional shortening was mainly due to decrease in the end-systolic dimension. These findings suggest that prolonged attacks of uncontrolled supraventricular tachycardia may result in left ventricular dysfunction, which is reversible after successful catheter ablation of the arrhythmias.
Article
Between 1969 and 1991, 11 patients were followed up for permanent junctional reciprocating tachycardia. The average age at diagnosis was 2 years and 4 months (1 day to 14 years). The tachycardia was diagnosed at routine examination in 5 cases and following an episode of cardiac failure in the other 6. Digitalis was prescribed in all patients with 4 good results, 5 average and 2 poor results. One patient, who remained in mild cardiac failure with digitalis therapy, died suddenly at the age of 9 years. In more recent cases, amiodarone was used from the onset or secondarily with good results in all patients. In 2 patients, in whom amiodarone was withdrawn after 3 months and 3 years' treatment, there was a recurrence of the tachycardia. No side effects of amiodarone therapy were observed in this series. Three patients were prescribed flecainide with 1 good and 2 average results. Propranolol, used in 2 cases, was associated with 1 average and 1 poor result. Disopyramide and Verapamil were ineffective. These results suggest that amiodarone is the drug to choose in permanent junctional reciprocating tachycardia but it must be given long term. The persistence of cardiac failure, poor control of the tachycardia or secondary effects of drug therapy should lead to consideration of non-medical management of the tachycardia.
Article
Ten patients aged 22 to 80 years (median 57) with severe left ventricular (LV) dysfunction and atrial fibrillation (AF) with rapid ventricular response were evaluated after therapy. Because most patients were unaware of their arrhythmia, duration was usually unknown. All patients had heart failure symptoms; 9 presented with New York Heart Association class III or IV disability, and 1 with class II disability. Initial LV ejection fraction ranged from 12 to 30% (median 25). No patient had symptomatic coronary artery disease (4 underwent angiography). Myocarditis and infiltrative processes were excluded by biopsy in 5 patients. All patients were considered initially to have idiopathic dilated cardiomyopathy with secondary AF. Ventricular rate was controlled in all patients, with sinus rhythm restored in 5. At follow-up (median 30 months, range 3 to 56), all patients were asymptomatic. LV ejection fraction after treatment ranged from 40 to 64% (median 52). It is concluded that in some patients initially considered to have idiopathic dilated cardiomyopathy, AF with rapid ventricular response may be the primary cause rather than the consequence of severe LV dysfunction. LV dysfunction may be completely reversible with ventricular rate control.
Article
Chronic supraventricular tachycardia (SVT) causes left ventricular (LV) dilatation and dysfunction. Changes in myocyte function and structure may be important factors in the development of SVT cardiomyopathy. Accordingly, LV function and isolated myocyte structure and function were examined in six pigs with pacing-induced SVT cardiomyopathy (3 weeks at 240 beats per minute) and six control pigs. LV function was examined by simultaneous echocardiography and catheterization, and isolated myocyte function was studied using computer-assisted video microscopy. Indexes of isolated myocyte contractile performance were examined in the unloaded, unattached state (31 control and 24 SVT cells) and after attachment to a basement membrane substrate (65 control and 45 SVT cells). LV fractional shortening and peak +dP/dt significantly decreased in SVT cells compared with control cells (12 +/- 2% versus 28 +/- 2%, and 842 +/- 61 versus 1,216 +/- 119 mm Hg/sec, respectively; p less than 0.05). Isolated myocyte percent shortening and normalized peak velocity of shortening of SVT myocytes adherent to a basement membrane were significantly lower than attached control myocytes (1.2 +/- 0.2% versus 4.3 +/- 0.3%, and 15 +/- 2 versus 37 +/- 5% resting cell length/sec, respectively; p less than 0.05). Similarly, in the unattached state, the extent and velocity of shortening of SVT myocytes were reduced by over 50% from control values. Contractile properties of attached and unattached cardiocytes were also examined in the presence of 2-8 mM extracellular Ca2+. For both attached and unattached SVT myocytes, responsiveness to increases in extracellular Ca2+ were significantly blunted from control values. Ultrastructural examination of SVT myocytes revealed that the percent volume of myofibrils within isolated myocytes was reduced from control values (46 +/- 7% versus 65 +/- 2%, p less than 0.05). In summary, SVT cardiomyopathy is probably due to a primary defect in isolated myocyte contractile performance. The reduced contractile function of SVT cardiomyopathic myocytes was associated with abnormalities in cytoarchitecture and Ca2+ responsiveness.
Article
The molecular and cellular mechanisms responsible for the dilated cardiomyopathy associated with chronic supraventricular tachycardia are not well understood. The purpose of this study was to examine Na+,K(+)-ATPase activity and distribution in a pacing induced model of dilated cardiomyopathy. Left ventricular function and Na+,K(+)-ATPase activity and distribution were examined in two groups of pigs: (1) atrially paced for 3 weeks (supraventricular tachycardia, 240 beats.min-1); (2) sham operated controls. 10 Yorkshire male swine (23-25 kg) were randomly assigned to the control group or the supraventricular tachycardia group. Left ventricular function was examined using simultaneous pressure echocardiography. Na+,K(+)-ATPase activity was determined in tissue homogenates by measuring the rate of p-nitrophenol-phosphate (pNPP) hydrolysis. Changes in content and distribution of Na+,K(+)-ATPase were examined immuno-histochemically in tissue sections. Left ventricular fractional shortening decreased significantly with supraventricular tachycardia as compared to controls, at 15 (SEM 3)% v 31(3)%, respectively p less than 0.05. Supraventricular tachycardia resulted in a significant increase in end diastolic dimension [5.0(0.3) cm v 3.5(0.2) cm, respectively p less than 0.05] and pressure [22(4)mm Hg v 6(2)mm Hg, respectively p less than 0.05]. Maximal Na+,K(+)-ATPase activity (microgram pNPP.mg-1 protein.h-1) was significantly lower with supraventricular tachycardia than in controls, at 0.45(0.12) v 0.64(0.06), respectively p less than 0.05. In the presence of 7 microM digitalis, Na+,K(+)-ATPase activity was inhibited by 68% in control and by 45% in supraventricular tachycardia homogenates (p less than 0.05). In control sections all left ventricular myocytes showed a uniform immunostaining pattern along the sarcolemma for Na+,K(+)-ATPase, whereas a focal loss of staining was observed in myocytes from the supraventricular tachycardia group. The congestive cardiomyopathy produced by supraventricular tachycardia was associated with a reduction in sarcolemmal Na+,K(+)-ATPase activity and changes in enzyme distribution. The findings also suggest a reduction in digitalis sensitivity with chronic supraventricular tachycardia. These alterations in Na+,K(+)-ATPase activity may be one potential mechanism responsible for the depressed left ventricular function associated with chronic supraventricular tachycardia.
Article
A 22-year-old man underwent electrophysiological evaluation for incessant wide QRS complex tachycardia with a pattern of right bundle-branch block and left axis deviation. The right and left ventricles were enlarged and hypokinetic consistent with dilated cardiomyopathy. Ventricular tachycardia was diagnosed by demonstrating capture and fusion beats, atrioventricular dissociation, and His potential activation that began after the onset of each QRS complex. Atrial extrastimuli and rapid atrial pacing failed to terminate the tachycardia and, although ventricular stimulation was successful, the tachycardia spontaneously restarted after one or two sinus beats. The tachycardia was unexpectedly abolished during catheter manipulation in the left ventricle and has not recurred during three-years of follow-up. The picture of a cardiomyopathy resolved. The ease with which the tachycardia was abolished by catheter manipulation implicate a therapeutic potential for catheter ablation of this type of tachycardia.
Article
Incessant supraventricular tachycardia (SVT) resistant to pharmacological agents may cause cardiac dysfunction requiring more aggressive therapy. We present the case of a 12-year-old postoperative Mustard patient who developed biventricular heart failure due to an atrial ectopic tachycardia resistant to amiodarone. Using endocavitary direct current fulguration techniques, catheter ablation of the His bundle was successfully performed after unsuccessful attempts at ablation of the ectopic atrial foci. After placement of a permanent transvenous rate responsive ventricular pacemaker, the patient's clinical status and cardiac function improved. Endocavitary fulguration of the His bundle is technically feasible after the Mustard procedure and should be considered for treatment of selective cases of pharmacologically resistant SVT.
Article
Chronic supraventricular tachycardia (SVT) causes a dilated cardiomyopathy and myocyte injury. Termination of SVT improves left ventricular (LV) function but is associated with LV hypertrophy. Changes in myocardial blood flow (MBF) that may accompany the development of and recovery from SVT cardiomyopathy might have a significant effect on LV function and myocyte structure. The goal of this study was to relate changes in LV function, myocyte composition, and coronary vascular structure to changes in MBF with the development and recovery of SVT cardiomyopathy. LV function and MBF were measured in three groups of conscious pigs: sham control (control; n = 8), after 3 weeks of atrial pacing (SVT, 240 beats per minute; n = 8), and after a 4-week recovery from SVT (post-SVT; n = 8) by echocardiography catheterization and microspheres. Measurements were made under three states: 1) at rest with a basal heart rate, 2) rapid atrial pacing (240 beats per minute), and 3) during adenosine infusion (1.5 mumol/l.kg-1.min-1) without pacing. LV myocyte, capillary, and arteriole morphometric studies were performed in five additional pigs from each group using histochemistry and electron microscopy. LV fractional shortening was lower and left atrial pressure was significantly higher in the SVT group compared with control at rest, during pacing, and with adenosine (p less than 0.05). In the post-SVT group, fractional shortening returned to control values at rest and with adenosine, but fell from control values with pacing (p less than 0.05). Left atrial pressure fell in the post-SVT but remained significantly higher than control (p less than 0.05). LV/body weight ratio was significantly increased in the post-SVT group (p less than 0.05). In all states, SVT LVMBF was significantly reduced from control values (rest, 0.8 +/- 0.3 versus 1.6 +/- 0.3 ml-min-1.g-1; pacing, 1.2 +/- 0.2 versus 3.1 +/- 0.3 ml.min-1.g-1; adenosine, 1.4 +/- 0.3 versus 4.4 +/- 0.4 ml.min-1.g-1, respectively, p less than 0.05). In the post-SVT group, LVMBF was similar to control at rest (1.3 +/- 0.2 ml.min-1.g-1) but was significantly lower than control with pacing and adenosine (2.0 +/- 0.4 and 2.5 +/- 0.5 ml.min-1.g-1, respectively, p less than 0.05). Myofibrillar content fell significantly with SVT compared with control (42 +/- 5 versus 61 +/- 3%, p less than 0.05) and returned to control values in the post-SVT group (64 +/- 3%). Capillary density remained unchanged in the SVT and post-SVT groups, but capillary luminal diameter decreased and arteriole diameter increased in the SVT group (p less than 0.05). The LV dysfunction and myocyte injury with SVT cardiomyopathy were associated with reduced MBF. Early recovery from SVT cardiomyopathy resulted in hypertrophy with normal MBF at rest, but significantly reduced coronary reserve.
Article
Incessant supraventricular tachyarrhythmia may lead to a reversible impairment of left ventricular (LV) function. This issue was investigated in 10 patients (aged 64 +/- 13 years) who underwent radiofrequency His bundle ablation for control of drug refractory, chronic atrial fibrillation (n = 9) and recurrent atrial flutter (n = 1). LV function was assessed by 2-dimensional guided M-mode echocardiography within 24 hours (baseline) and 49 +/- 18 days (follow-up) after successful ablation, both during VVI pacing at 70 beats/min. Fractional shortening increased from 28 +/- 9% at baseline to 35 +/- 8% at follow-up (p = 0.006). This increase in fractional shortening was due to a significant reduction of end-systolic diameter from 41 +/- 10 to 36 +/- 10 mm (p = 0.02), whereas there was no appreciable change in end-diastolic diameter (56 +/- 7 to 55 +/- 10 mm; p = 0.5). These changes were substantially greater in patients with baseline impairment of LV function (fractional shortening less than 27%). Fractional shortening increased by 12% (p = 0.14) in patients with normal LV function (n = 5) and by 44% (p = 0.02) in those with impaired LV function at baseline (n = 5). The greater increase in fractional shortening in patients with preexisting LV impairment was due to a more pronounced decline in end-systolic dimensions (-11.9%; p = 0.08) compared with that of patients with normal LV function at baseline (-9.21%; p = 0.2). End-diastolic diameter showed no significant change in either group (-3.53% [p = 0.8] and -0.58% [p = 0.4]).(ABSTRACT TRUNCATED AT 250 WORDS)
Article
Chronic supraventricular tachycardia (SVT) results in left ventricular (LV) dilatation and dysfunction. However, the underlying mechanisms responsible for LV failure in this setting are not known. LV force production is dependent on the coupling of myocytes to the extracellular matrix, which is mediated through the basement membrane. This study was designed to determine whether alterations in myocyte geometry and basement membrane attachment are associated with LV failure in a pacing-induced model of cardiomyopathy. Echocardiographic measurement of LV function was performed in six pigs after 3 weeks of pacing-induced SVT (240 beats/min) and in eight sham-operated controls. Myocytes from these hearts were isolated, and attachment studies to specific components of the basement membrane were performed using laminin, fibronectin, and collagen IV. The SVT group when compared with the control group showed a significant reduction of LV fractional shortening (14 +/- 2% versus 31 +/- 2%, respectively; p less than 0.05), increased end-diastolic dimension (50 +/- 1 versus 35 +/- 1 mm, respectively; p less than 0.05), and lengthening of isolated myocytes (196 +/- 18 versus 142 +/- 9 microns, respectively; p less than 0.05). Myocyte attachment to laminin (50 micrograms/ml) was significantly decreased at 60 minutes in the SVT group compared with the control group (18.2 +/- 4.5 versus 60.9 +/- 4.5 cells/mm2, respectively; p less than 0.05). Similar reductions in myocyte attachment to fibronectin and collagen IV were observed. Ultrastructural examination of LV sections revealed focal disruptions of the basement membrane-sarcolemmal interface and a reduced number of sarcolemmal festoons in SVT hearts compared with control hearts (0.8 +/- 0.6 versus 2.8 +/- 0.8/4 microns, respectively; p less than 0.05). These alterations in myocyte morphology and basement membrane attachment may contribute to the LV failure associated with chronic SVT. Further, these structural changes may play a significant role in the progression of ventricular dysfunction as well as recovery from chronic SVT.
Article
Chronic supraventricular tachycardia (SVT) causes left ventricular (LV) dilatation and dysfunction. Termination of SVT appears to reduce LV size and improve function. However, changes in myocyte structure and morphology that accompany the development and regression of SVT-induced cardiomyopathy have not been studied. Accordingly, we measured LV function using echocardiography and catheterization in three groups of six pigs each: 3 weeks of atrial pacing (SVT; 240 beats/min), 4-week recovery from SVT (PST), and sham-operated controls. At each of these three end points, isolated myocyte dimensions and nuclear number were measured using fluorescence, and the volume percent of myocytes and myofibrils was computed from tissue sections using stereological techniques. SVT resulted in reduced LV fractional shortening (15 +/- 3% versus 31 +/- 2%, p less than 0.05), increased end-diastolic dimension (5.6 +/- 0.8 versus 3.8 +/- 0.2 cm, p less than 0.05), and no change in mass (2.6 +/- 0.1 versus 2.6 +/- 0.2 g/kg, p = NS) compared with controls. Myocyte length significantly increased with SVT (171 +/- 9 versus 109 +/- 11 microns, p less than 0.05), without significant changes in cell width (28 +/- 2 versus 26 +/- 2 microns). Nuclear number did not change with SVT; however, nuclear area/myocyte area significantly increased compared with controls (9.5 +/- 0.8 versus 8.7 +/- 0.8 x 10(-2), p less than 0.05). The volume percent of myocytes within the ventricular wall and the volume percent of myofibrils within myocytes decreased with SVT compared with controls (72 +/- 3% versus 80 +/- 3% and 45 +/- 5% versus 63 +/- 4%, respectively, p less than 0.05), with no change in total myocyte volume (54.2 +/- 2.7 versus 54.3 +/- 1.8 microns3 x 10(12)). In the PST group, LV fractional shortening returned to control values; however, there was persistent dilatation (end-diastolic dimension: 4.2 +/- 0.1 cm, p less than 0.05), and LV hypertrophy developed (3.3 +/- 0.3 g/kg, p less than 0.05). Increased myocyte length (158 +/- 5 microns, p less than 0.05) and width (33 +/- 2 microns, p less than 0.05) were observed in the PST group. The volume percent of myocytes and myofibrils returned to control values, with total myocyte volume significantly increased in the PST group compared with the control and SVT groups (74.5 +/- 2.6 microns3 x 10(12), p less than 0.05). In addition, the number of nuclei per myocyte in the PST group significantly increased from control values (5.1 +/- 0.1 versus 4.0 +/- 0.1, p less than 0.05).(ABSTRACT TRUNCATED AT 400 WORDS)
Article
Chronic supraventricular tachycardia causes a dilated cardiomyopathy in man. Terminating this tachycardia appears to result in symptomatic improvement; however, its effects on left ventricular (LV) volume, mass, and function have not been fully examined. Accordingly, hemodynamic studies using simultaneous echocardiography and catheterization were performed in three groups of pigs: 1) those subjected to rapid left atrial pacing (240 beats/min) for 3 weeks (SVT, n = 8), 2) those subjected to supraventricular tachycardia for 3 weeks followed by termination of pacing and a 4-week recovery period (PSVT, n = 9), and 3) sham-operated controls (CTR, n = 10). Systolic pump function was assessed using fractional shortening (FS), peak ejection rate [peak (-)dD/dt], and maximum rate of pressure development [peak (+)dP/dt]. Diastolic function was assessed using the time constant of isovolumic pressure decline (tau), peak early diastolic filling rate [peak (+)dD/dt], the chamber stiffness constant (Kc), and the myocardial stiffness constant (Km). Supraventricular tachycardia caused LV dilation (end-diastolic dimension [EDD] increased from 3.5 +/- 0.4 cm in CTR to 4.9 +/- 0.5 cm in SVT, p less than 0.05) but no change in LV mass (LV weight-to-body weight ratio [LV/BW]) was 2.58 +/- 0.3 g/kg in CTR and 2.66 +/- 0.4 g/kg in SVT), all indexes of systolic function became abnormal (FS fell from 30 +/- 4% in CTR to 13 +/- 5% in SVT, p less than 0.05), and the indexes of relaxation and filling were slowed (tau increased from 36 +/- 3 msec in CTR to 51 +/- 13 msec in SVT, p less than 0.05). There were no significant changes in Kc or Km. After terminating the supraventricular tachycardia, LV volume fell but remained greater than that in CTR (EDD was 4.2 +/- 0.4 cm in PSVT, p less than 0.05 versus CTR) and substantial LV hypertrophy developed (LV/BW was 3.48 +/- 0.5 g/kg in PSVT, p less than 0.05 versus CTR). Systolic function returned to normal (FS was 31 +/- 5% in PSVT) but diastolic function remained abnormal. In PSVT, tau remained prolonged (49 +/- 12 msec, p less than 0.05 versus CTR), Kc increased from 3.7 +/- 1.0 in CTR to 7.4 +/- 1.2 (p less than 0.05), and Km increased from 4.4 +/- 1.5 in CTR to 13.9 +/- 9.7 (p less than 0.05). Thus, the improvement in systolic function that occurs after the termination of supraventricular tachycardia is associated with the development of LV hypertrophy and persistent diastolic dysfunction.
Article
A patient with dilated cardiomyopathy and supraventricular tachycardia presumed to be of sinus origin was referred for cardiac transplantation. The extreme rate of the tachycardia during exercise, profound fluctuations in heart rate, and the presence of an abnormal P wave axis suggested the diagnosis of incessant ectopic atrial tachycardia rather than compensatory sinus tachycardia. Electrophysiologic study with endocardial activation sequence mapping confirmed the diagnosis of an ectopic left atrial automatic tachycardia, after which surgical cryoablation of the left atrial focus was carried out successfully and sinus rhythm was restored. Serial radionuclide angiocardiograms obtained before and after surgery demonstrated a very rapid recovery of left ventricular function to nearly normal within the first month after surgery, followed by further improvement to normal over the next several months. The diagnosis of tachycardia-related cardiomyopathy should be seriously considered in any patient with apparently end-stage dilated cardiomyopathy and persistent resting tachycardia.
Article
To test the hypothesis that atrial enlargement can develop as a consequence of atrial fibrillation, left and right atrial dimensions were measured echocardiographically at two different time points in patients with atrial fibrillation. Patients were selected who initially had normal atrial sizes and who had no evidence of significant structural or functional cardiac abnormalities other than atrial fibrillation either by history or two-dimensional and Doppler echocardiography. Fifteen patients were studied (12 men and three women; mean age, 67.3 years). Average time between studies was 20.6 months. Three orthogonal left atrial dimensions and two right atrial dimensions were measured, and all were found to increase significantly between studies. Also, highly significant increases in calculated left atrial volume (from 45.2 to 64.1 cm3, p less than 0.001) and right atrial volume (from 49.2 to 66.2 cm3, p less than 0.001) were observed. The relative extents of left and right atrial volume increase did not differ, and left ventricular size did not change significantly between studies. These results indicate that atrial enlargement can occur as a consequence of atrial fibrillation. The maintenance of sinus rhythm, therefore, may prevent atrial enlargement and its adverse clinical effects.
Article
We reviewed the records of 26 infants with congenital junctional ectopic tachycardia (JET) from seven institutions to examine the evolution in the management of this tachycardia that is difficult to treat. JET was defined electrocardiographically as an incessant tachycardia with normal QRS morphology and atrioventricular (AV) dissociation. The ventricular rate ranged from 140 to 370 beats/min (mean, 230 beats/min); 16 of 26 patients had cardiac failure. Treatment success was defined as a stable decrease in the rate of JET, below 150 beats/min; partial success was a significant decrease of JET rate with alleviation of symptoms. All patients received digoxin with no significant effect. Propranolol was given to 16 patients, with two successes and one partial success. Combinations of other conventional agents were used in 11 patients with two successes; 14 patients were treated with amiodarone, which resulted in eight successes and three partial successes; three patients died suddenly on medical treatment (amiodarone, one patient; propranolol, one patient; or amiodarone plus propranolol, one patient); sudden AV block was a possible cause and consequently, two later patients had pacemaker implantation as well as medical treatment. His catheter ablation was successfully performed twice but contributed to death in a newborn; three surgical His ablations were performed for intractable JET with two successes and one death. The overall mortality was 35%. Among survivors, treatment has been stopped without any complications in five patients ranging in age from 10 months to 8 years (mean, 3.5 years). It seems that amiodarone alone is the best drug for treatment of congenital JET; necessity for permanent pacing remains unsettled. His ablation should be reserved only for intractable JET.
Article
Right atrial ectopic tachycardia (RAET) with secondary cardiac dysfunction can be difficult to differentiate from primary dilated cardiomyopathy (CMP) with sinus tachycardia. In an attempt to separate RAET from CMP by noninvasive testing, routine surface electrocardiograms (EGGs), 24-hour ambulatory ECGs (Holter monitors), and echocardiograms of patients with RAET (n = 34) and CMP (n = 33) were reviewed. RAET atrial rates were significantly faster than CMP rates on the resting ECG and on Holter monitoring; 12 of 33 patients with RAET had resting ECG rates greater than 150% of predicted normal values for age but none of 32 patients with CMPs had resting ECG rates in this range. Mean P wave axis in the horizontal plane was more posterior in patients with RAET and was less than 0 degrees (negative in lead V2) in 8 of 29 patients with RAET but in 1 of 33 patients with CMP. Second-degree atrioventricular (AV) block was observed in 12 of 33 patients with RAET but in none of 33 with CMP. Shortening fraction less than 10% was found in 13 of 33 individuals with CMP but in only 1 of 27 with RAET. We conclude that noninvasive studies can help identify RAET among patients with poor functioning hearts and right atrial tachycardia.
Article
Chronic supraventricular tachycardia has been associated with ventricular dysfunction in humans and animals. However, this ventricular failure is poorly characterized, and the ultrastructural consequences of supraventricular tachycardia are unknown. We serially examined right and left ventricular function, endomyocardial ultrastructure, and creatine kinase activity in eight pigs at base line and again at 1, 2, and 3 wk following rapid atrial pacing. Left and right ventricular ejection fractions fell significantly from base line after 1 wk of chronic tachycardia. Three weeks of chronic pacing resulted in further deterioration in ejection fractions. Significant biventricular chamber dilatation developed and was associated with a reduction in end-diastolic wall thickness after 2 wk of tachycardia. Mitochondrial injury and diminished mitochondrial cytochrome oxidase staining of subendocardial myocytes were observed after 2 wk of tachycardia. Endomyocardial creatine kinase activity fell from control levels following 2 wk of pacing. Postmortem examination revealed a reduction in left ventricular wall thickness compared with 14 control animals. Fibrosis occurred along the subendocardial layer in paced animals, and glycogen content was also reduced. In summary, chronic supraventricular tachycardia resulted in severe biventricular pump dysfunction and chamber dilatation that were associated with ultrastructural alterations and reduced enzyme activity of the subendocardial myocytes. These ultrastructural and metabolic changes may be potential mechanisms responsible for the ventricular dysfunction and dilatation observed in this model.
Article
Seven of 17 patients with incessant supraventricular tachycardia caused by an accessory pathway with a long retrograde conduction time were seen with symptoms or echocardiographic signs of a tachycardia-induced cardiomyopathy. Three patients were in New York Heart Association functional class II with dyspnea and four were in class III. Eight patients (six with tachycardia-induced cardiomyopathy) underwent surgery because of failure of medical treatment (including one patient in functional class I) and one underwent direct current catheter ablation of the atrioventricular (AV) node. In six patients echocardiograms recorded before and after the procedure were available. Before surgery or direct current ablation the mean left ventricular ejection fraction was 36.3 ± 8.7%. the left ventricular end-diastolic diameter 55.7 ± 7.6 mm and the left ventricular end-systolic diameter 44.3 ± 7.8 mm. A mean of 21.6 ± 6.8 months after the procedure the mean left ventricular ejection fraction increased to 58.6 ± 8.0%, the left ventricular end-diastolic diameter decreased to 49.0 ± 3.6 mm and the left ventricular end-systolic diameter decreased to 32.2 ± 2.7 mm; all six patients were in functional class I. These results confirm that control of incessant tachycardia leads to a regression of symptoms and signs of cardiomyopathy and progressive normalization of the dimensions of the heart. Because of these findings, surgery should be considered early in patients with an accessory AV pathway and incessant tachycardia. The presence of a tachycardia-induced cardiomyopathy should therefore be an indication for surgery rather than a contraindication.
Article
It was assumed that the availability of new antiarrhythmic drugs and new surgical techniques might allow medical or nonexcisional surgical treatment in many young children with incessant ventricular tachycardia. Fourteen infants and young children less than 5 years of age were evaluated and treated for incessant ventricular tachycardia. Medical treatment was pursued up to the use of amiodarone with a type Ib or Ic antiarrhythmic drug unless the patient became hemodynamically unstable. Patients underwent surgery when these drug regimens failed or when moderate congestive heart failure was present. Seven patients were successfully treated medically and seven underwent surgical treatment. Of those treated surgically, five had cryothermic lesions and two had excisions. Five of the surgically treated patients required temporary additional medical treatment. Follow-up ranged from 12 to 53 months (mean 28). Eleven of the 14 patients are currently not taking any antiarrhythmic medication. No patient required a pacemaker, none received anticongestive medications and none died.
Article
The pathophysiologic role of atrial natriuretic factor and other neuroendocrine variables in relation to serum sodium and renal function was evaluated in 15 conscious dogs with severe chronic ventricular pacing-induced heart failure (250 beats/min for 5.1 +/- 0.4 weeks). Six sham-operated dogs observed over an 8 week period served as controls. Development of heart failure was characterized by a progressive increase in plasma norepinephrine, renin activity and aldosterone from control values of 293 +/- 15 pg/ml, 1.4 +/- 0.4 ng/ml per h and 124 +/- 42 pg/ml, respectively, to 1,066 +/- 96 pg/ml, 10.2 +/- 2.4 ng/ml per h and 577 +/- 151 pg/ml (all p less than 0.01), respectively, at severe heart failure. In contrast to other neuroendocrine variables, plasma atrial natriuretic factor increased from a control level of 243 +/- 74 pg/ml to a peak concentration of 724 +/- 149 pg/ml (p less than 0.01) at 2 weeks, then declined and plateaued at twice the level of the control value as severe heart failure developed. At severe heart failure, serum sodium decreased from 147 +/- 0.6 to 141.8 +/- 2.1 mmol/liter (p less than 0.05), whereas urea increased from 6.0 +/- 0.5 to 7.8 +/- 0.6 mmol/liter (p less than 0.05). The change in serum sodium concentration correlated with plasma renin activity and aldosterone (r = -0.77, -0.88, respectively, both p less than 0.01), but not with norepinephrine or atrial natriuretic factor. When sinus rhythm was restored, 14 dogs were observed for 48 to 72 h and 8 dogs were followed up for another 4 weeks after cessation of pacing.(ABSTRACT TRUNCATED AT 250 WORDS)