Tchavdar N Shalganov

Tchavdar N Shalganov
National Cardiology Hospital, Bulgaria · Department of Cardiology

MD, PhD

About

119
Publications
28,579
Reads
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2,170
Citations
Additional affiliations
December 2018 - present
National Cardiology Hospital, Bulgaria
Position
  • Professor (Full)
Description
  • Full-time consulting cardiologist and electrophysiologist
July 2015 - present
National Cardiology Hospital, Bulgaria
Position
  • CRM head
Description
  • Full-time consulting cardiologist and electrophysiologist
May 2010 - December 2018
National Cardiology Hospital, Bulgaria
Position
  • Professor (Associate)
Description
  • Full-time consulting cardiologist and electrophysiologist
Education
April 2006 - December 2008
National Cardiology Hospital, Bulgaria
Field of study
  • Electrophysiological parameters for differentiating macroreentrant from focal atrial tachycardias and for defining the atrium of origin of the arrhythmia
October 1984 - December 1990
Medical Academy, Sofia, Bulgaria
Field of study
  • Medicine

Publications

Publications (119)
Article
Full-text available
Myocardial infarction with non-obstructive coronary arteries (MINOCA) is a syndrome of diverse etiology and unclear pathogenesis, with an incidence of 5-15% and varying prognosis. Cardiac magnetic resonance imaging (MRI) is playing an increasing role in the diagnosis of MINOCA and in distinguishing the causes that led to it, while being at the same...
Article
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This study presents data from the national electronic registry BG-EPHY on electrophysiologic (EP) cardiac ablations in 2021. Material and methods: This is a retrospective study of a full one-year sample of the BG-EPHY registry. Sex and age distribution of the patients, number of ablations, electroanatomic mapping (EAM), irrigated and cryoablations,...
Article
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A 52-year- old patient with previous catheter ablation of A-V nodal reentrant tachycardia (AVNRT) had a redo procedure for reported recurrence. During the study, AVNRT was not inducible, but a previously unrecognized left-sided Mahaim-type accessory pathway was diagnosed and ablated successfully.
Preprint
Full-text available
A 52-year-old patient with previous catheter ablation of AV nodal reentrant tachycardia (AVNRT) had a redo procedure for reported recurrence. During the study AVNRT was not inducible, but a previously unrecognized left-sided Mahaim type accessory pathway was diagnosed and ablated successfully.
Article
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Background Epidemiological studies in atrial fibrillation (AF) illustrate that clinical complexity increase the risk of major adverse outcomes. We aimed to describe European AF patients’ clinical phenotypes and analyse the differential clinical course. Methods We performed a hierarchical cluster analysis based on Ward’s Method and Squared Euclidea...
Article
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The catheter ablation of cardiac arrhythmias causes myocardial destruction and increase of the cardiac troponin and C-reactive protein (CRP). Data regarding dynamics of high-sensitivity troponin during irrigated ablation are scarce, and for diagnostic electrophysiological studies (EPS) are lacking. We aimed to study the periprocedural dynamics of h...
Article
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Atrial fibrillation (AF) is the most common arrhythmia in adults and requires permanent anticoagulation in the presence of risk factors. Left atrial (LA) thrombus is found in a significant minority of patients despite anticoagulant treatment. We aimed to estimate the prevalence of LA thrombosis on uninterrupted oral anticoagulation (OAC) in AF patien...
Article
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We present the case of a 23-year-old male diagnosed with a complex congenital heart disease (with single ventricle physiology) which necessitated many surgical interventions including total cavopulmonary connection. The patient presents with recurrent (almost daily) highly symptomatic atrial tachycardia with rapid ventricular rate and poor haemodyn...
Article
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This study presents data from the national electronic registry BG-EPHY on electrophysiologic (EP) cardiac ablations in 2019 and 2020. Material and methods: This is a retrospective study of a full two-year sample of the BG-EPHY registry. Sex and age distribution of the patients, number of ablations, electroanatomic mapping (EAM), irrigated ablations...
Article
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Anatomical variants of pulmonary venous drainage in the left atrium are often found. Divergent results have been reported on the impact of variant anatomy on atrial fi brillation (AF) recurrence after catheter ablation. We aimed to study the frequency of different anatomical variants of pulmonary venous drainage and their relationship with documente...
Article
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The presence of left atrial (LA) dilation, as well as the presence and extent of LA zones with abnormal myocardial voltage are among the factors for recurrence of atrial fibrillation (AF) after pulmonary vein isolation (PVI). Our aim was to study the rate of recurrences after first ablation for AF in patients with and without LA dilation or abnorma...
Article
Full-text available
There is paucity of studies correlating the left atrial (LA) dilation and the LA total and abnormal voltage areas in patients with atrial fibrillation (AF). We sought to determine the area of LA and its segments by high-density mapping in patients with paroxysmal AF, and to correlate the LA dilation defined by echocardiography with the total and th...
Article
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A female patient with nonautomatic focal atrial tachycardia with paraHissian location of the focus and previously unsuccessful ablation attempt in the right atrium (RA) is presented. Electroanatomic mapping demonstrated sequential activation of the anteroseptal area of the RA, anteroseptal area of the left atrium and non-coronary sinus of Valsalva...
Article
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Introduction: Radiofrequency catheter ablation of idiopathic ventricular arrhythmias originating in the para-Hisian region could be challenging because of a potential risk of iatrogenic atrioventricular block. Uncommonly, shift of the exit site during the ablation can be observed. Consequently, different approaches of radiofrequency catheter ablati...
Article
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Purpose: To compare the length of the hospital stay for scheduled catheter ablation of atrial fibrillation and/or flutter in patients with heparin bridge versus patients on uninterrupted oral anticoagulation. Methods: Single centre retrospective study of patients with atrial fibrillation and/or flutter, taking oral anticoagulant and subjected to ca...
Article
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Purpose: To present catheter ablation as treatment modality for recurrent post-infarction ventricular tachycardia (VT) in local setting. Material and methods: Descriptive single center retrospective study of patients with old inferior myocardial infarction and left ventricular aneurysm, who underwent irrigated radiofrequency catheter ablation for r...
Preprint
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BACKGROUND. The clinical effectiveness of primary prevention implantable cardioverter defibrillator (ICD) therapy is under debate. It is urgently needed to better identify patients who benefit from prophylactic ICD therapy. The EUropean Comparative Effectiveness Research to Assess the Use of Primary ProphylacTic Implantable Cardioverter Defibrillat...
Article
Background: The clinical effectiveness of primary prevention implantable cardioverter defibrillator (ICD) therapy is under debate. It is urgently needed to better identify patients who benefit from prophylactic ICD therapy. The EUropean Comparative Effectiveness Research to Assess the Use of Primary ProphylacTic Implantable Cardioverter Defibrilla...
Article
Full-text available
Purpose: To confirm the safety of the radiofrequency catheter ablation (RFCA) for complex atrial arrhythmias during uninterrupted oral anticoagulation (OAC) and to study the safety of RFCA during uninterrupted OAC for non-complex arrhythmias. Material and methods: From April 25 2017 on, data were collected prospectively on consecutive patients on...
Article
Full-text available
Papillary muscles can be the source of ventricular arrhythmias with distinct electrocardiographic and electrophysiologic characteristics that discriminate them from other ventricular arrhythmias in patients with structurally normal hearts. Triggered activity or abnormal automaticity is suggested as the underlying electrophysiological mechanism. Cat...
Article
Full-text available
Aims. The clinical effectiveness of primary prevention implantable cardioverter defibrillator (ICD) therapy is under debate. The EUropean Comparative Effectiveness Research to Assess the Use of Primary ProphylacTic Implantable Cardioverter Defibrillators (EU-CERT-ICD) aims to assess its current clinical value. Methods and results. EU-CERT-ICD is a...
Article
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A short review of methods for ECG diagnosis of some genetic heart diseases is presented. The electrophysiological mechanisms underlying the characteristic ECG changes are shortly reviewed. Several simple non-invasive provocative tests and ECG modifications applicable in everyday practice are described.
Article
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The purpose of this study was to determine correlation between hemodynamic and morphological features with cardiovascular magnetic resonance (CMR) in patients with ARVC. Revised Task force criteria (TFC) do not include morphological CMR features for diagnosis of ARVC to avoid false positive results. Nevertheless, CMR gives most comprehensive evalua...
Article
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Purpose: To study the correlation between the sudden prolongations of the atrio-Hisian (AH) interval with ≥50 ms during burst and programmed atrial stimulation, and to define whether the AH jump during burst atrial pacing is a reliable diagnostic criterion for dual AV nodal physiology. Methods: Retrospective data on 304 patients with preliminary...
Article
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A short review of the widely accepted criteria for ECG diagnosis and differential diagnosis of wide QRS-complex tachycardias is presented. The most used diagnostic algorithms are also presented. The readers are given the opportunity to test their own knowledge
Article
Full text available at: http://www.tandfonline.com/eprint/CdvDUiE724iumJZXBMrH/full Objective: The non-fluoroscopic navigation (NFN) is known to reduce the fluoroscopic time during catheter ablation of various arrhythmias. We aimed to study the impact of NFN over several procedural parameters during radiofrequency (RF) catheter ablation of the cav...
Article
Full-text available
Focal tachycardias originating from the left atrial appendage are extremely rare. They present typical P-wave morphology on the 12-lead ECG. We present a case with such an arrhythmia, in which the ECG recorded persistent atypical atrial flutter. The correct diagnosis was made only by an electrophysiological study. Successful catheter ablation was d...
Article
Full-text available
Background: Left atrial macroreentrant tachycardias (LA MRT) are diagnosed infrequently. Catheter ablation of LA MRT has not been reported so far in Bulgaria. Material and methods: Electrophysiologic study and catheter ablation were performed in 4 patients with recurrent persistent atypical atrial fl utter. The study was done using multipolar cathe...
Article
Full-text available
Summary: Ventricular arrhythmia is not a rare clinical phenomenon, especially in patients with structural heart disease. Treatment mode depends on the type of arrhythmia present and aims to both relieve symptoms and improve prognosis. Contemporary Guidelines explore a wide range of clinical scenarios and prescribe the best proven therapeutic choice...
Article
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A short review is presented of the key points of the new 2015 ESC guidelines for the management of patients with ventricular arrhythmias and the prevention of sudden cardiac death
Article
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We present a patient with congenital long QT syndrome and normal baseline left ventricular function, in whom several years after the implantation of an automatic cardioverter-defi brillator severe left ventricular dysfunction was found together with a peculiar ECG during antibradycardia pacing. The mechanism for the appearance of the unusual ECG an...
Article
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We present the first case of catheter ablation of recurrent post-myocardial infarction ventricular tachycardia in Bulgaria in a patient with previous inferior myocardial infarction and left ventricular aneurism.
Conference Paper
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Purpose: To study the correlation between the sudden jump-like prolongations of the AH interval by �=>50 ms during incremental atrial pacing and during programmed atrial stimulation, and to define whether the AH jump during incremental atrial pacing can serve as a reliable diagnostic criterion for the presence of dual AV nodal physiology. Methods:...
Conference Paper
Full-text available
Purpose: To study the impact of non-fluoroscopic navigation (NFN) on several procedural and clinical parameters during radiofrequency (RF) catheter ablation (CA) of the cavo-tricuspid isthmus (CTI) in patients with CTI-dependent atrial flutter. Methods: Data about 124 consecutive patients with CTI CA performed were retrospectively collected. Patien...
Article
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Idiopathic ventricular arrhythmias (VAs) originating from the left ventricular outfl ow tract (LVOT) are infrequent. Aim: The aim of the study was to present local experience in the catheter ablation of these VAs. Methods: A single center retrospective study of consecutive patients with idiopathic LVOT VAs took place. Demographic data, data on VAs,...
Article
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The achievement of complete electrical isolation of the pulmonary veins during ablation for atrial fi brillation is of paramount importance for the procedural success. The occurrence of this phenomenon in an integrated approach combining circumferential ablation and electrical disconnection is presented with intracardiac recordings. The advantages...
Article
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The case is presented of a patient with recurrent ventricular tachycardia, arrhythmogenic right ventricular cardiomyopathy and implanted cardioverter-defibrillator. The device misdiagnosed ventricular tachycardia as supraventricular and consequently withheld potentially life-saving antitachycardia therapy. An easy way to rapid and correct determina...
Article
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Atrial tachycardias (ATs) frequently develop in patients with congenital heart defects (CHDs). This study aimed to evaluate the effects of extensive atrial scar formation on the total atrial activation time (TAAT) and its relation to the tachycardia cycle length (CL) to classify AT.METHODS AND RESULTS: Seventy-one patients were included and divided...
Article
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A middle-aged patient with arterial hypertension and dyslipidaemia presented with a 10-year history of recurrent sustained monomorphic ventricular tachycardia (VT) provoked by exertion or emotional affect (figure 1A). He had been treated with propafenone and amiodarone. Four years before, the standard 12-lead and modified Fontaine ECG in sinus rhyt...
Article
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A rare variant of non-arrhythmogenic ventricular preexcitation (fasciculoventricular accessory pathway) is presented. Its identification is possible only with electrophysiological study and is of paramount importance in order to avoid unnecessary intervention with potential for serious complications.
Article
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The superior vena cava (SVC) is known to be a potential source of focal atrial tachycardias. Not uncommonly these tachycardias trigger atrial fibrillation or flutter. Focal ablation is safe and effective in eliminating arrhythmogenic foci within the SVC. We present the case of a patient with focal atrial tachycardia arising from the SVC. During pre...
Article
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Focal right ventricular tachycardia is relatively uncommon. It usually arises from specific anatomic locations. A 59-year-old woman with a structurally normal heart and an automatic cardioverter-defibrillator implanted beforehand presented with drug-resistant incessant ventricular tachycardia for which 1786 anti-tachycardia pacing therapies and 119...
Article
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The ventricular arrhythmias originating from the left ventricular outfl ow tract are part of the spectrum of the idiopathic ventricular arrhythmias. We present the cases of three patients with this type of arrhythmia cured successfully with radiofrequency catheter ablation. We discuss some of the particularities of those arrhythmias with an emphasi...
Article
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Early activation at the His bundle (HB) region or proximal coronary sinus (CS) during focal atrial tachycardias (FATs) often necessitates biatrial mapping. Analysis of CS electrograms (EGMs) consisting of a near-field (N) component from CS musculature and a far-field (F) component from left atrial (LA) myocardium can uncover LA activation preceding...
Article
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The intermittent narrowing of the QRS complex during ventricular tachycardia is usually due to ventricular capture by and/or fusion with antegradely conducted sinus impulse. We present a case of postinfarction ventricular tachycardia with repeated narrowing of the QRS in the setting of another arrhythmogenic substrate, responsible for a supraventri...
Article
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Bundle-branch reentry is an uncommon but clinically relevant form of ventricular tachycardia. It is usually seen in patients with dilated cardiomyopathy – non-ischemic, valvular, and ischemic, in myotonic dystrophy, and in isolated conduction disturbances of the His-Purkinje system. It has been described in patients with structurally normal heart a...
Article
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Noncompaction cardiomyopathy is a rare genetic disease caused by arrest of the normal endomyocardial embryogenesis. The clinical manifestations are indistinguishable from those in dilated cardiomyopathy. The diagnosis is made by cardiac imaging modalities, and treatment is focused on the major clinical manifestations – heart failure, arrhythmias, s...
Article
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Catheter ablation for atrial fibrillation is a recognized treatment modality when certain indications and contraindications are respected. Methods: Some demographic, clinical, and procedural characteristics of the patients with paroxysmal or persistent atrial fibrillation treated by catheter ablation in our institution, are presented. Data about mo...
Article
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A second, and even a first transseptal puncture, may prove to be difficult or infeasible in some patients. Two patients are presented with infeasible first transseptal puncture, in which left atrial access was obtained with the regular transseptal set and application of radiofrequency energy through the Brockenbrough needle. Successful and uncompli...
Chapter
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ST-елевация в отвеждания V 1-V 3 без връзка с исхемия, елек-тролитни нарушения или структурно сърдечно заболяване датира от 1953 год. 1 Едва през 1992 г. обаче Pedro и Josep Brugada описват 8 пациенти с ST-елевация в десните гръдни отвеждания, десен бедрен блок (ДББ) и внезапна сърдечна смърт и обособяват самостоятелен клиникоелектрокардиографски с...
Article
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Background: Right ventricular (RV) pacing creates artificial left ventricular (LV) dyssynchrony and thus can be used as a surrogate for left bundle branch block (LBBB). Assuming this, our aim was to assess the evolution of the QRS width in chronically paced pediatric patients with and without structural heart disease (SHD). Methods: A group of 99 p...
Article
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A 26-year-old woman with partial atrioventricular (AV) canal defect surgically closed with pericardial patch in a mode that the triangle of Koch had become part of the left atrium underwent successful slow pathway ablation for slow-fast AV nodal reentrant tachycardia. Transseptal approach was used because of the atypical post-operative anatomy. Tra...
Article
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Forty-four-year-old male patient with surgical closure of ostium secundum type atrial septal defect at the age of 9 years had undergone radiofrequency catheter ablation of the cavotricuspid isthmus because of recurrent drug-resistant typical isthmus-dependent atrial flutter, with bi-directional isthmus block achieved. Only few days later he started...
Article
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Atrial fibrillation is the most common arrhythmia. It affects millions of patients, especially elderly, and mostly men. A number of risk factors for developing atrial fibrillation are known. Most of them are common conditions or heart diseases. The prognosis in atrial fibrillation depends on the late sequelae of the arrhythmia – heart failure, stro...
Article
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Article
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We report on a case of an adult male patient with previously unknown coronary anomaly and acute myocardial infarction in the territory of the left anterior descending artery (LAD). The coronary angiography showed a single coronary artery with intertruncal course, arising from the right coronary sinus, and thrombotic occlusion of the LAD. Successful...
Poster
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Poster ”Analysis of atrial electrograms in His and coronary sinus recordings can identify the chamber of origin of focal atrial tachycardias”
Article
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Full text available at http://www.tandfonline.com/eprint/ps6MEmAyvFGba8cDYKZi/full The objective was to study atrial activation intervals and their relation to the tachycardia cycle length (TCL) as electrophysiologic parameters differentiating focal (FAT) from macroreentrant atrial tachycardias (MRAT) originating in the right atrium. In 21 patien...
Article
Full-text available
A case is presented of a patient with arrhythmogenic right ventricular cardiomyopathy and drug refractory recurrent monomorphic ventricular tachycardia. The use of electroanatomic mapping helped to demonstrate the arrhythmia mechanism and the arrhythmia substrate. Radiofrequency catheter ablation was performed of a critical and easily accessed part...
Thesis
Full-text available
Quantitative electrophysiological parameters differentiating focal (FAT) from macroreentrant atrial tachycardias (MRAT) and defining the atrium of origin are currently lacking. The aim of this doctoral thesis is to find out such quantitative criteria. The atrial activation times and their relation to the tachycardia cycle length, as well as the ear...