Roberto A Santilli

Clinica veterinaria Malpensa, Samarate, Varese, Italy · Cardiology

Background Supraventricular tachycardias (SVTs), despite having various anatomical substrates and pathophysiological mechanisms, frequently show similar electrocardiographic presentations. Objectives To locate and characterize atrial deflections (ADs) on 12‐lead electrocardiograms in dogs with sustained rapid SVT and assess the utility of differen...

Standard transthoracic echocardiography is considered the non-invasive gold standard for the diagnosis of most cardiac diseases. Defining reproducibility, repeatability, and reliability of this exam is imperative to reduce errors in clinical evaluations. The present study aimed at: (1) evaluating the reproducibility and repeatability of 15 echocard...

Evaluating canine electrocardiograms (ECG) require skilled veterinarians, but current availability of veterinary cardiologists for ECG interpretation and diagnostic support is limited. Developing tools for automated assessment of ECG sequences can improve veterinary care by providing clinicians real-time results and decision support tools. We imple...

Standard transthoracic echocardiography is considered the non-invasive gold standard for the diagnosis of most cardiac diseases. Defining reproducibility, repeatability, and reliability of this exam is imperative to reduce errors in clinical evaluations. The present study aimed at: 1) evaluating the reproducibility and repeatability of 15 echocardi...

IntroductionThe aim of the study was to describe the electrocardiographic features of ventricular pre-excitation (VPE) patterns characterized by the presence of delta (δ) wave, short P-δQRS interval, wide δQRS complexes in dogs with right-sided accessory pathways.Animals, materials and methodsTwenty-six dogs with a confirmed accessory pathways (AP)...

Introduction: The aim of the study was to describe the electrocardiographic features of ventricular pre-excitation (VPE) patterns in dogs with right-sided accessory pathways. Animals, materials and methods: Twenty-six dogs with confirmed accessory pathway (AP) via electrophysiological mapping were included in the study. The following parameters wer...

Background There is a lack of clinical data on hypertrophic cardiomyopathy (HCM) in dogs. Hypothesis/Objectives To investigate signalment, clinical signs, diagnostic findings, and survival in dogs with HCM. Animals Sixty‐eight client‐owned dogs. Methods Retrospective multicenter study. Medical records were searched between 2003 and 2015. The dia...

Objectives To define electrocardiographic features of complete left bundle branch block (LBBB) and right bundle branch block (RBBB), and the use of R-peak time (RPT) to identify interventricular dyssynchrony in dogs with BBB. Animals, Materials and Methods Twelve-lead ECG tracings of 20 dogs with RBBB, 20 with LBBB, and 60 healthy dogs were retros...

• SVT may affect only the LA in the dog. • Spectral and 2D Doppler echocardiography help confirm that an SVT is confined to the LA. • Left atrial SVT was identified by comparing MV and TV inflows via spectral Doppler.

Diagnosing the early stages of canine Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) is complicated by day-to-day arrhythmia variability, and absence of reliable, transthoracic echocardiographic features. Definitive diagnosis requires histopathologic identification of transmural fibrofatty replacement of the right ventricle. Reduction of im...

Introduction/Objectives Inherited or acquired arrhythmic disorders and cardiac disease have been associated with sudden cardiac death (SCD) in dogs. The electrical mechanism related to death in most of these cases is unknown. The aim of this retrospective study was to describe arrhythmic events in dogs that experienced SCD during Holter monitoring....

Idiopathic pericarditis (IP) and pericardial mesothelioma (PM) are causes of pericardial effusion in dogs. Pericardiectomy can be a definitive treatment in the case of idiopathic pericardial effusion or a short-term intervention for mesothelioma. The aim of the present study was to investigate which histopathologic parameters are correlated with cl...

Four dogs were referred to our institution for incessant supraventricular tachycardias causing weakness; congestive heart failure was present in one dog. At admission all dogs had a surface electrocardiogram showing a narrow QRS complex tachycardia with a ventricular rate ranging from 80 to 300 bpm, variable atrioventricular conduction ratio from 1...

Objectives To identify the predictive value on time to onset of heart failure (HF) or cardiac death of clinical, radiographic and echocardiographic variables, as well as cardiac biomarkers N-terminal pro brain natriuretic peptide (NT-proBNP) and cardiac troponin I in dogs with preclinical myxomatous mitral valve disease (MMVD). Animals One-hundred...

R-peak time (RPT) is an electrocardiographic parameter that represents the time taken for electrical activation to spread from the endocardium to the epicardium. In human medicine, right ventricular RPT is measured from lead V1 to lead V2, and left ventricular RPT from lead V5 to lead V6. The aim of the present study was to define RPT duration in a...

The identification of the heart rhythm during an episode of transient loss of consciousness (TLOC) is considered the reference standard method to elucidate the underlying aetiology. This study aimed to characterise heart rhythm in dogs during TLOC using Holter and external loop recorder monitoring. We retrospectively reviewed 24-h Holter monitoring...

Myocarditis is one of the most complex diagnosis in veterinary cardiology: the clinical symptoms are nonspecific and the clinical course is extremely variable, the prevalence in dogs and cats is unknown and probably underestimated, the pathophysiology is still unclear and the specific treatment is controversial. Many of these shortcomings are relat...

Background The Evaluation of pimobendan in dogs with cardiomegaly caused by preclinical myxomatous mitral valve disease (EPIC) study monitored dogs with myxomatous mitral valve disease (MMVD) as they developed congestive heart failure (CHF). Objectives To describe the changes in clinical and radiographic variables occurring as dogs with MMVD and c...

Introduction: Efficacy of renin-angiotensin-aldosterone system (RAAS) blockade using angiotensin-converting enzyme inhibitors (ACEi) in dogs with preclinical myxomatous mitral valve disease (MMVD) is controversial. Hypothesis: Administration of spironolactone (2-4 mg q 24 h) and benazepril (0.25-0.5 mg q 24 h) in dogs with preclinical MMVD, not...

Objective: To determine the prevalence of nucleic acid from selected cardiotropic pathogens in endomyocardial biopsy samples from dogs with unexplained myocardial and rhythm disorders (UMRD) and compare prevalence with that for a group of control dogs with congenital heart disease (CHD). Animals: 47 client-owned dogs. Procedures: Right ventric...

Background Epidemiologic knowledge regarding noncardiovascular and all‐cause mortality in apparently healthy cats (AH) and cats with preclinical hypertrophic cardiomyopathy (pHCM) is limited, hindering development of evidence‐based healthcare guidelines. Objectives To characterize/compare incidence rates, risk, and survival associated with noncard...

Aortic dissection (AD) is characterized by bleeding within the aortic wall or a tear in the intimal layer of the aortic wall, resulting in the passage of blood from the aortic lumen into the tunica media. In cases of AD, a floating, intimal flap in the aortic lumen divides the lumen into a true portion, with flow present, and a false portion, with...

Pacemaker implantation is considered as a standard procedure for treatment of symptomatic bradycardia in both dogs and cats. Advanced second-degree and third-degree atrioventricular blocks, sick sinus syndrome, persistent atrial standstill, and vasovagal syncope are the most common rhythm disturbances that require pacing to either alleviate clinica...

Objective: To assess recording accuracy of right atrial and ventricular depolarization during 12-lead ECG when precordial lead V1 was positioned at each of 5 locations on the thorax of dogs with various thoracic conformations. Animals: 60 healthy client-owned dogs. Procedures: 20 dogs were allocated to each of 3 groups (brachymorphic, mesomorp...

Introduction: Accessory pathways (APs) in dogs are mostly right-sided, display nondecremental conduction, and mediate atrioventricular reciprocating tachycardias (AVRTs). Radiofrequency catheter ablation (RFCA) is considered the first-line therapy in human patients to abolish electrical conduction along APs. Animals: Seventy-six consecutive clie...

A 3-year-old castrated male domestic shorthair presented to the Cornell University Hospital for Animals for acute onset respiratory distress. Thoracic radiographs, echocardiogram, and electrocardiogram (ECG) revealed left-sided congestive heart failure, myocardial thickening with left atrial dilation, and sinus rhythm conducted with a left bundle b...

In humans, accessory pathways (APs) in an anteroseptal and midseptal position are often challenging to ablate because of their close proximity with the conduction pathways of the atrioventricular junction. The use of low-energy ablation techniques can be useful to reduce the risk of permanently damaging the atrioventricular node and the His bundle....

Background Hypertrophic cardiomyopathy is the most prevalent heart disorder in cats and principal cause of cardiovascular morbidity and mortality. Yet, the impact of preclinical disease is unresolved. Hypothesis/Objectives Observational study to characterize cardiovascular morbidity and survival in cats with preclinical nonobstructive (HCM) and ob...

This report describes transient trifascicular block in three cats presented with lethargy and inappetence, and elevated cardiac troponin I concentrations. The electrocardiogram (ECG) of cat 1 showed a sinus rhythm with pronounced first-degree atrioventricular (AV) block, right bundle branch block, and left anterior fascicular block. The ECG of cat...

Table S1. Ordinal scoring system for clinical variables recorded at baseline.Table S2. P‐values for the between‐group comparison of ordinal quality of life and clinical variables at each of the visits up to and including the visit at 24 months.

Figure S1. Four Forest plots illustrating the hazard ratios and their 95% confidence intervals obtained from the four multivariable Cox proportional hazards analysis models.

Background: Changes in clinical variables associated with the administration of pimobendan to dogs with preclinical myxomatous mitral valve disease (MMVD) and cardiomegaly have not been described. Objectives: To investigate the effect of pimobendan on clinical variables and the relationship between a change in heart size and the time to congesti...

Background Pimobendan is effective in treatment of dogs with congestive heart failure (CHF) secondary to myxomatous mitral valve disease (MMVD). Its effect on dogs before the onset of CHF is unknown. Hypothesis/Objectives Administration of pimobendan (0.4- o.6mg/kg/d in divided doses) to dogs with increased heart size secondary to preclinical MMVD,...

A 6-year-old, male, mongrel dog was presented for acute onset of dyspnea and cough. At admission, the dog was cachectic and severely depressed. The electrocardiogram showed a sinus rhythm conducted with left bundle truncular branch block and interrupted by frequent multiform ventricular ectopic beats organized in allorhythmias. Thoracic radiographs...

Background: Pimobendan is effective in treatment of dogs with congestive heart failure (CHF) secondary to myxomatous mitral valve disease (MMVD). Its effect on dogs before the onset of CHF is unknown. Hypothesis/objectives: Administration of pimobendan (0.4-0.6 mg/kg/d in divided doses) to dogs with increased heart size secondary to preclinical...

Objectives: To document the electrocardiographic findings of vagally-induced paroxysmal atrial fibrillation following a presumed reflex syncopal episode in the dog. Animals: Seven dogs with a syncopal episode followed by a paroxysm of atrial fibrillation recorded on a 24-hour Holter. Methods: Twenty-four hour Holter monitors were retrospective...

Fig S3. A forest plot showing the hazard ratio and 95% confidence intervals associated with variables remaining in the final explanatory mutivariable Cox Proportional Hazards analysis with time to the primary endpoint (congestive heart failure or cardiac related death) as the dependent variable. Circles represent the hazard ratio and the horizontal...

Fig S4. Kaplan Meier survival curves plotting the estimated percentage of dogs in each group in the intention to treat population that have not yet died, against time. There were 179 dogs in the pimobendan group and 180 dogs in the placebo group at the outset. CI, confidence interval; NA, Not able to calculate.

Fig S1. Flow diagram illustrating the pre‐planned decision making process at the time of the interim analysis.

Fig S2. A forest plot showing the hazard ratio and 95% confidence interval estimated from Cox Proportional Hazards analysis for treatment effect from the multivariate analysis (Pimobendan MV), from a univariate analysis (Pimobendan only) and from bivariate Cox Proportional Hazards analyses including treatment analyzed together with each of the 32 b...

Table S1 Different events and the consequence of those events in the different time to event analyses undertaken on the per protocol population. Abbreviation: CHF, congestive heart failure.

Background: Atrioventricular block (AVB) is a conduction abnormality along the atrioventricular node that, depending on etiology, may lead to different outcomes. Objectives: To evaluate variations of intrinsic rhythm (IR) in dogs that underwent pacemaker implantation (PMI). Animals: Medical records of 92 dogs affected by 3rd degree atrioventri...

The familiar arrhythmogenic disorders can be associated with cardiostructural diseases or be present in dogs who show no heart diseases. In dogs, disorders associated with arrhythmogenic cardiostructural diseases are represented by arrhythmogenic cardiomyopathy and dilated cardiomyopathy, while the sinus node dysfunction, the atrioventricular acces...

Background Pulmonary hypertension (PH) is common in dogs with myxomatous mitral valve disease (MMVD) but its effect on clinical outcome has not been investigated.Hypothesis/objectivesThe presence of PH worsens the outcome in dogs with MMVD. To compare survival times of dogs with MMVD and PH to those without PH.AnimalsTwo hundred and twelve client-o...

Radiofrequency catheter ablation is the first line treatment for most common supraventricular arrhythmias reported in the dog, such as focal atrial tachycardia, atrial flutter, and bypass-tract mediated tachycardia as well as for ventricular tachycardia refractory to medical treatment. Iatrogenic atrioventricular block was the most common complicat...

Arrhythmogenic right ventricular cardiomyopathy is a familial heart disease characterized by a progressive replacement of myocardium with fibro-fatty tissue. These structural changes are accompanied by functional changes with the onset of ventricular arrhythmias and myocardial dysfunction. In veterinary medicine, this disease has been reported spor...

Objective: To characterize the electrocardiographic features of the atrial repolarization (Ta) wave in dogs with third-degree atrioventricular (AV) block. Sample: ECGs of 36 dogs with third-degree AV block and no identifiable structural heart diseases. Procedures: Standard 12-lead ECGs were acquired with a digital system, and measurements were...

Myxomatous mitral valve disease (MMVD) is an important cause of morbidity and mortality in dogs. To compare, throughout the period of follow-up of dogs that had not yet reached the primary endpoint, the longitudinal effects of pimobendan versus benazepril hydrochloride treatment on quality-of-life (QoL) variables, concomitant congestive heart failu...

A 5-year-old male English Bulldog was presented with a 1-year history of paroxysmal supraventricular tachycardia (SVT) partially responsive to amiodarone. At admission the surface ECG showed sustained runs of a narrow QRS complex tachycardia, with a ventricular cycle length (R-R interval) of 260 ms, alternating with periods of sinus rhythm. Endocar...

Five dogs were presented to our institution for fatigue caused by an incessant supraventricular tachycardia. In all dogs, an ECG on admission showed a narrow QRS complex tachycardia with a median ventricular cycle length of 220 ms (range 180–360 ms), and a positive atrial depolarization identifiable in the ST segment following the previous QRS comp...

Electrocardiographic tracings of an English Bulldog referred for cardiogenic shock due to an orthodromic atrioventricular reciprocating tachycardia conducted with intraventricular conduction disturbance and mimicking ventricular tachycardia (VT) are presented. At admission the surface ECG showed a wide QRS complex tachycardia (WCT) that was convert...

Isorhythmic atrioventricular dissociation (IAVD) is a rhythm disturbance in which atria and ventricles are driven by independent pacemakers at equal or nearly equal rates. To describe electrocardiographic and electrophysiologic features of IAVD in a group of 11 Labrador Retrievers and its possible correlation with focal junctional tachycardia (FJT)...

To describe the electrocardiographic characteristics of ventricular tachycardia arising from the right ventricular outflow tract and the particular association between this arrhythmia and the presence of localised right ventricular outflow tract enlargement in English bulldogs. Five English bulldogs were referred with a history of syncope or cardio...

Pacemaker implantation is a common treatment for patients with symptomatic bradiarrhythmias in dogs. Several studies have documented a different rate of complications in dogs underwent PM implantation. This retrospective study evaluate rate and features of major and minor complications occurred within 30 days after endocardial pacemaker implantatio...

Describe the presence of arrhythmias in dogs with myxomatous mitral valve disease (MMVD) and the potential association with class of heart failure and left atrial enlargement. Compare the standard electrocardiogram (ECG) with Holter monitoring for assessing heart rate (HR). EXPERIMENTAL PROCEDURE: The study group of 36 dogs weighing less than 20 kg...

The aim of this retrospective study was to evaluate the utility of transcutaneous external pacing (TEP) during transvenous pacemaker implantation in dogs. Eighty-two pacemakers were implanted in 77 dogs because of third-degree atrioventricular block (AVB) (58 cases; 70.7 per cent), sinus node dysfunction (SND) (nine cases; 11.0 per cent), high-grad...

Recognition that many cardiovascular diseases maybe inherited imply the need for the developing of breed screening programs. These programs need that the clinical and instrumental techniques for screening being accurately standardized as modality of inheritance and clinical presentation are complex. The development of accurate standards for screeni...

Focal atrial tachycardia (FAT) is a common supraventricular tachycardia in dogs. To evaluate electrophysiologic characteristics and topographic distribution of FAT. Sixteen dogs with symptomatic FAT. Retrospective case series. Electrophysiological studies were performed to test the inducibility of documented and no documented arrhythmias. Once indu...

Two dogs were presented for episodic weakness caused by a very rapid supraventricular tachycardia with a ventricular rate of 360 bpm and 300 bpm, respectively. Electrocardiography showed narrow QRS complex tachycardia in both subjects, the first one with a fixed 2:1 atrioventricular block, and the second with variable degrees of atrioventricular bl...

To evaluate the diagnostic value of an implantable loop recorder (ILR) in dogs with unexplained syncope. Prospective case series. 12 dogs with recurrent unexplained syncope. An ILR was surgically inserted in a pocket created in the subcutaneous tissues of the left hemithorax of each dog. The ILRs were programmed for manual and automatic activation,...

Introduction: syncope is defined as a transient loss of consciousness caused by a global cerebral oxygen deprivation. Causes of syncope can include arrhythmias, neurally-mediated reflex faint, dysautonomic disorders and diseases that induce pulmonary hypertension. Holter monitoring is an important diagnostic tool to identify the cause of transient...

A 5-year-old English Bulldog was presented for acute onset of syncope and fatigue caused by sustained ventricular tachycardia with left bundle block morphology and inferior axis. This arrhythmia had the electrocardiographic features of a ventricular tachycardia arising from the right ventricular outflow tract (RVOT), as described in an experimental...

Pulmonary hypertension has been associated with mitral insufficiency caused by chronic degenerative valve disease in dogs. Our aim was to search for associations between left atrial to aortic root ratio, end-systolic and end-diastolic volume indices, and changes in the right ventricular to right atrial pressure gradient as estimated by the peak vel...

Myxomatous mitral valve disease (MMVD) continues to be an important cause of morbidity and mortality in geriatric dogs despite conventional therapy. Pimobendan in addition to conventional therapy will extend time to sudden cardiac death, euthanasia for cardiac reasons, or treatment failure when compared with conventional therapy plus benazepril in...

The 12-lead surface ECG is validated for differentiating supraventricular tachycardias (SVT) in humans. Despite the description of SVT in veterinary medicine, no studies have analyzed the electrocardiographic features of this type of arrhythmias in dogs. To describe the specific electrocardiographic criteria used to differentiate the most common SV...

The aim of this study was to analyse the results of 6years (1999-2004) of mandatory breed screening for congenital heart disease in Boxer dogs using physical examination and echocardiography. Records of 1283 Boxers were reviewed and 165 dogs (12.86%) were found to be affected by heart disease, with aortic and pulmonic stenosis being the most freque...

There are few studies evaluating the natural history and prognostic variables in chronic mitral valve disease (CMVI) in a heterogeneous population of dogs. To estimate survival and prognostic value of clinical and echocardiographic variables in dogs with CMVI of varying severity. Five hundred and fifty-eight dogs belonging to 36 breeds were studied...

Many viruses have been identified in pericardial fluid and in tissue samples from humans with pericarditis by means of molecular diagnostics. In canine idiopathic pericardial effusion there is as yet no conclusive evidence to support the involvement of an infectious agent. This study was designed to investigate a possible relationship between idiop...

To evaluate the anatomic distribution and electrophysiologic properties of accessory pathways (APs) in dogs. Case series. 10 dogs with tachyarrhythmias associated with an AP. Each dog underwent electrophysiologic testing to determine the inducibility of documented and undocumented arrhythmias and to identify location, conduction properties, and ant...

Radiofrequency catheter ablation (RFCA) is widely used as a curative therapeutic strategy in human beings with paroxysmal supraventricular tachycardia (SVT), but rarely applied in animals. This report describes successful RFCA of atrioventricular accessory pathways (AP) in two dogs with episodic weakness caused by frequent paroxysms of supraventric...

The purpose of this study was to investigate the prognostic value of various clinical, ECG, echocardiographic, and Doppler echocardiographic variables in dogs with dilated cardiomyopathy. The relationship to survival of 11 variables was evaluated in 63 dogs. Studied variables were age at time of diagnosis, class of heart failure (HF), dyspnea, asci...

The primary indication for pacemaker therapy in dogs and cats is symptomatic bradyarrhythmia that does not respond to medical treatment. Different techniques have been used for pacemaker implantation since 1968. Transvenous endocardial pacemaker implantation is a minimally invasive method and represents the first choice of treatment for this type o...

The case records of 58 German Shepherds (GS group) affected by mitral valve prolapse (MVP) and/or mitral valve regurgitation (MR), and 49 dogs weighing < 15 kg (D group), affected by chronic valvular disease (CVD) were reviewed. The dogs of the GS group were presented more often without a detectable heart murmur (p < 0.01), and less frequently with...

Renal biopsies were carried out on 229 dogs using an echo-assisted, semi-automatic method. Complications arising after the biopsy were also evaluated. The biopsies were examined for the accuracy of diagnosis and the presence of histologically demonstrable primary renal pathologies. A retrospective study of the observed lesions and parenchymal echog...

An overview of clinical, laboratory, and diagnostic imaging features of congenital porto-systemic shunt (PSS) in dogs and cats is presented through the analysis of recent literature, and personal case log. Particular emphasis is given to diagnostic accuracy of ultrasonographic examination of PSS in the evaluation of shunt vessel anatomy, and of anc...

To histologically identify glomerular lesions in dogs infected with Leishmania organisms. 41 dogs (17 sexually intact males and 14 sexually intact and 10 ovariohysterectomized females) that had positive results when tested for leishmaniosis as determined by use of serologic evaluation (indirect fluorescent antibody test, titers of 1:80 to 1:640) an...