Radiofrequency catheter ablation for treatment of bundle branch reentrant ventricular tachycardia: results and long-term follow-up

Progressive outcomes of bundle branch reentrant ventricular tachycardia in patients without structural heart disease

BACKGROUND

Ablation strategies to treat bundle branch reentrant ventricular tachycardia (BBRT) are well described. However, reports of long-term follow-up outcomes in BBRT patients without structural heart disease (SHD) are limited.

OBJECTIVE

The purpose of this study was to investigate the long-term follow-up prognosis of BBRT patients without SHD.

METHODS

Changes in electrocardiographic and echocardiographic parameters were used to evaluate progression during follow-up. Potential pathogenic candidate variants were screened using a specific gene panel.

RESULTS

Eleven consecutive BBRT patients without obvious SHD based on echocardiographic and cardiovascular magnetic resonance imaging results were enrolled. Median age was 20 (11-48) years, and median follow-up time was 72 months. During follow-up, PR interval [206 (158-360) ms vs 188 (158-300) ms; P = .018] and QRS duration [187 (155-240) ms vs 164 (130-178) ms; P = .008] each increased significantly compared with postablation. Right- and left-sided chamber dilation and reduced left ventricular ejection fraction (LVEF) also were observed. Clinical deterioration or events occurred in 8 patients: 1 sudden death; 3 both complete heart block and reduced LVEF; 2 significantly reduced LVEF; and 2 prolonged PR interval. Genetic testing results showed that 6 of 10 patients (excluding the patient with sudden death) had ≥1 potential pathogenic candidate variants.

CONCLUSION

Further deterioration of His-Purkinje system conduction was observed in young BBRT patients without SHD after ablation. The His-Purkinje system may be the first target of genetic predisposition.

Recurring episodes of bundle branch reentry ventricular tachycardia due to aortitis preceded by SARS-CoV-2 infection: a case report

BACKGROUND

SARS-CoV-2 may trigger both vasculitis and arrhythmias as part of a multisystem inflammatory syndrome described in children as well as in adults following COVID-19 infection with only minor respiratory symptoms. The syndrome denotes a severe dysfunction of one or more extra-pulmonary organ systems, with symptom onset approximately 2-5 weeks after the COVID-19 infection. In the present case, a seemingly intractable ventricular tachycardia preceded by SARS-CoV2 infection was only managed following the diagnosis and management of aortitis.

CASE PRESENTATION

A 69-year-old woman was hospitalized due to syncope, following a mild COVID-19 infection. She presented with paroxysmal atrial fibrillation and intermittent ventricular tachycardia interpreted as a septum-triggered bundle branch reentry ventricular tachycardia, unaffected by amiodaron, lidocaine and adenosine. A CT-scan revealed inflammation of the aortic arch, extending into the aortic root. In the following days, the tachycardia progressed to ventricular storm with intermittent third-degree AV block. A temporary pacemaker was implanted, and radiofrequency ablation was performed to both sides of the ventricular septum after which the ventricular tachycardia was non-inducible. Following supplemental prednisolone treatment, cardiac symptoms and arrythmia subsided, but recurred after tapering. Long-term prednisolone treatment was therefore initiated with no relapse in the following 14 months.

CONCLUSION

We present a rare case of aortitis complicated with life-threatening ventricular tachycardia presided by Covid-19 infection without major respiratory symptoms. Given a known normal AV conduction prior to the COVID-19 infection, it seems likely that the ensuing aortitis in turn affected the septal myocardium, enabling the reentry tachycardia. Generally, bundle branch reentry tachycardia is best treated with radiofrequency ablation, but if it is due to aortitis with myocardial affection, long-term anti-inflammatory treatment is mandatory to prevent relapse and assure arrhythmia control. Our case highlights importance to recognize the existence of the multisystem inflammatory syndrome in adults (MIS-A) following COVID-19 infection in patients with alarming cardiovascular symptoms. The case shows that the early use of an CT-scan was crucial for both proper diagnosis and treatment option.

Latent Causes of Sudden Cardiac Arrest

Inherited arrhythmia syndromes are a common cause of apparently unexplained cardiac arrest or sudden cardiac death. These include long QT syndrome and Brugada syndrome, with a well-recognized phenotype in most patients with sufficiently severe disease to lead to cardiac arrest. Less common and typically less apparent conditions that may not be readily evident include catecholaminergic polymorphic ventricular tachycardia, short QT syndrome and early repolarization syndrome. In cardiac arrest patients whose extensive testing does not reveal an underlying etiology, a diagnosis of idiopathic ventricular fibrillation or short-coupled ventricular fibrillation is assigned. This review summarizes our current understanding of the less common inherited arrhythmia syndromes and provides clinicians with a practical approach to diagnosis and management.

Diagnosis and Management of Complex Reentrant Arrhythmias Involving the His-Purkinje System

The His-Purkinje system is a network of bundles and fibres comprised of specialised cells that allow for coordinated, synchronous activation of the ventricles. Although the histology and physiology of the His-Purkinje system have been studied for more than a century, its role in ventricular arrhythmias has recently been discovered with the ongoing elucidation of the mechanisms leading to both benign and life-threatening arrhythmias. Studies of Purkinje-cell electrophysiology show multiple mechanisms responsible for ventricular arrhythmias, including enhanced automaticity, triggered activity and reentry. The variation in functional properties of Purkinje cells in different areas of the His-Purkinje system underlie the propensity for reentry within Purkinje fibres in structurally normal and abnormal hearts. Catheter ablation is an effective therapy in nearly all forms of reentrant arrhythmias involving Purkinje tissue. However, identifying those at risk of developing fascicular arrhythmias is not yet possible. Future research is needed to understand the precise molecular and functional changes resulting in these arrhythmias.

2019 HRS/EHRA/APHRS/LAHRS expert consensus statement on catheter ablation of ventricular arrhythmias: executive summary

Ventricular arrhythmias are an important cause of morbidity and mortality and come in a variety of forms, from single premature ventricular complexes to sustained ventricular tachycardia and fibrillation. Rapid developments have taken place over the past decade in our understanding of these arrhythmias and in our ability to diagnose and treat them. The field of catheter ablation has progressed with the development of new methods and tools, and with the publication of large clinical trials. Therefore, global cardiac electrophysiology professional societies undertook to outline recommendations and best practices for these procedures in a document that will update and replace the 2009 EHRA/HRS Expert Consensus on Catheter Ablation of Ventricular Arrhythmias. An expert writing group, after reviewing and discussing the literature, including a systematic review and meta-analysis published in conjunction with this document, and drawing on their own experience, drafted and voted on recommendations and summarized current knowledge and practice in the field. Each recommendation is presented in knowledge byte format and is accompanied by supportive text and references. Further sections provide a practical synopsis of the various techniques and of the specific ventricular arrhythmia sites and substrates encountered in the electrophysiology lab. The purpose of this document is to help electrophysiologists around the world to appropriately select patients for catheter ablation, to perform procedures in a safe and efficacious manner, and to provide follow-up and adjunctive care in order to obtain the best possible outcomes for patients with ventricular arrhythmias.

2019 HRS/EHRA/APHRS/LAHRS expert consensus statement on catheter ablation of ventricular arrhythmias

Ventricular arrhythmias are an important cause of morbidity and mortality and come in a variety of forms, from single premature ventricular complexes to sustained ventricular tachycardia and fibrillation. Rapid developments have taken place over the past decade in our understanding of these arrhythmias and in our ability to diagnose and treat them. The field of catheter ablation has progressed with the development of new methods and tools, and with the publication of large clinical trials. Therefore, global cardiac electrophysiology professional societies undertook to outline recommendations and best practices for these procedures in a document that will update and replace the 2009 EHRA/HRS Expert Consensus on Catheter Ablation of Ventricular Arrhythmias. An expert writing group, after reviewing and discussing the literature, including a systematic review and meta-analysis published in conjunction with this document, and drawing on their own experience, drafted and voted on recommendations and summarized current knowledge and practice in the field. Each recommendation is presented in knowledge byte format and is accompanied by supportive text and references. Further sections provide a practical synopsis of the various techniques and of the specific ventricular arrhythmia sites and substrates encountered in the electrophysiology lab. The purpose of this document is to help electrophysiologists around the world to appropriately select patients for catheter ablation, to perform procedures in a safe and efficacious manner, and to provide follow-up and adjunctive care in order to obtain the best possible outcomes for patients with ventricular arrhythmias.

2019 HRS/EHRA/APHRS/LAHRS expert consensus statement on catheter ablation of ventricular arrhythmias: Executive summary

Ventricular arrhythmias are an important cause of morbidity and mortality and come in a variety of forms, from single premature ventricular complexes to sustained ventricular tachycardia and fibrillation. Rapid developments have taken place over the past decade in our understanding of these arrhythmias and in our ability to diagnose and treat them. The field of catheter ablation has progressed with the development of new methods and tools, and with the publication of large clinical trials. Therefore, global cardiac electrophysiology professional societies undertook to outline recommendations and best practices for these procedures in a document that will update and replace the 2009 EHRA/HRS Expert Consensus on Catheter Ablation of Ventricular Arrhythmias. An expert writing group, after reviewing and discussing the literature, including a systematic review and meta-analysis published in conjunction with this document, and drawing on their own experience, drafted and voted on recommendations and summarized current knowledge and practice in the field. Each recommendation is presented in knowledge byte format and is accompanied by supportive text and references. Further sections provide a practical synopsis of the various techniques and of the specific ventricular arrhythmia sites and substrates encountered in the electrophysiology lab. The purpose of this document is to help electrophysiologists around the world to appropriately select patients for catheter ablation, to perform procedures in a safe and efficacious manner, and to provide follow-up and adjunctive care in order to obtain the best possible outcomes for patients with ventricular arrhythmias.

2019 HRS/EHRA/APHRS/LAHRS expert consensus statement on catheter ablation of ventricular arrhythmias

Ventricular arrhythmias are an important cause of morbidity and mortality and come in a variety of forms, from single premature ventricular complexes to sustained ventricular tachycardia and fibrillation. Rapid developments have taken place over the past decade in our understanding of these arrhythmias and in our ability to diagnose and treat them. The field of catheter ablation has progressed with the development of new methods and tools, and with the publication of large clinical trials. Therefore, global cardiac electrophysiology professional societies undertook to outline recommendations and best practices for these procedures in a document that will update and replace the 2009 EHRA/HRS Expert Consensus on Catheter Ablation of Ventricular Arrhythmias. An expert writing group, after reviewing and discussing the literature, including a systematic review and meta-analysis published in conjunction with this document, and drawing on their own experience, drafted and voted on recommendations and summarized current knowledge and practice in the field. Each recommendation is presented in knowledge byte format and is accompanied by supportive text and references. Further sections provide a practical synopsis of the various techniques and of the specific ventricular arrhythmia sites and substrates encountered in the electrophysiology lab. The purpose of this document is to help electrophysiologists around the world to appropriately select patients for catheter ablation, to perform procedures in a safe and efficacious manner, and to provide follow-up and adjunctive care in order to obtain the best possible outcomes for patients with ventricular arrhythmias.

Syncope After Transcatheter Aortic Valve Replacement: Two Faces of Abnormal Intraventricular Conduction

Conduction system damage is the most common complication of transcatheter aortic valve replacement (TAVR), which frequently requires placement of a permanent pacemaker. Bundle branch reentry (BBR) is a well-recognized mechanism of ventricular tachycardia (VT) in the setting of abnormal intraventricular conduction. We describe a case of a patient with post-TAVR intraventricular conduction abnormalities who presented with intermittent advanced atrioventricular block and BBR VT and discuss the potential risks, diagnosis, and management of BBR after TAVR.

2019 HRS/EHRA/APHRS/LAHRS expert consensus statement on catheter ablation of ventricular arrhythmias: Executive summary

Ventricular arrhythmias are an important cause of morbidity and mortality and come in a variety of forms, from single premature ventricular complexes to sustained ventricular tachycardia and fibrillation. Rapid developments have taken place over the past decade in our understanding of these arrhythmias and in our ability to diagnose and treat them. The field of catheter ablation has progressed with the development of new methods and tools, and with the publication of large clinical trials. Therefore, global cardiac electrophysiology professional societies undertook to outline recommendations and best practices for these procedures in a document that will update and replace the 2009 EHRA/HRS Expert Consensus on Catheter Ablation of Ventricular Arrhythmias. An expert writing group, after reviewing and discussing the literature, including a systematic review and meta-analysis published in conjunction with this document, and drawing on their own experience, drafted and voted on recommendations and summarized current knowledge and practice in the field. Each recommendation is presented in knowledge byte format and is accompanied by supportive text and references. Further sections provide a practical synopsis of the various techniques and of the specific ventricular arrhythmia sites and substrates encountered in the electrophysiology lab. The purpose of this document is to help electrophysiologists around the world to appropriately select patients for catheter ablation, to perform procedures in a safe and efficacious manner, and to provide follow-up and adjunctive care in order to obtain the best possible outcomes for patients with ventricular arrhythmias.

2019 HRS/EHRA/APHRS/LAHRS expert consensus statement on catheter ablation of ventricular arrhythmias

Ventricular arrhythmias are an important cause of morbidity and mortality and come in a variety of forms, from single premature ventricular complexes to sustained ventricular tachycardia and fibrillation. Rapid developments have taken place over the past decade in our understanding of these arrhythmias and in our ability to diagnose and treat them. The field of catheter ablation has progressed with the development of new methods and tools, and with the publication of large clinical trials. Therefore, global cardiac electrophysiology professional societies undertook to outline recommendations and best practices for these procedures in a document that will update and replace the 2009 EHRA/HRS Expert Consensus on Catheter Ablation of Ventricular Arrhythmias. An expert writing group, after reviewing and discussing the literature, including a systematic review and meta-analysis published in conjunction with this document, and drawing on their own experience, drafted and voted on recommendations and summarized current knowledge and practice in the field. Each recommendation is presented in knowledge byte format and is accompanied by supportive text and references. Further sections provide a practical synopsis of the various techniques and of the specific ventricular arrhythmia sites and substrates encountered in the electrophysiology lab. The purpose of this document is to help electrophysiologists around the world to appropriately select patients for catheter ablation, to perform procedures in a safe and efficacious manner, and to provide follow-up and adjunctive care in order to obtain the best possible outcomes for patients with ventricular arrhythmias.

Bundle branch reentrant ventricular tachycardia: review and case presentation

Bundle branch reentrant ventricular tachycardia (BBRVT) is characterized by a unique, fast (200-300 beats/min), monomorphic wide complex tachycardia (WCT) associated with syncope, hemodynamic compromise, and cardiac arrest. It is challenging to diagnose, requiring a His bundle recording and specific pacing maneuvers. The overall incidence has been reported to be up to 20% among patients with non-ischemic cardiomyopathy (NICM) undergoing electrophysiologic studies. We report a case of BBRVT in a patient with ischemic cardiomyopathy (ICM) presenting as a WCT with recurrent implantable-cardioverter-defibrillator (ICD) shocks. We describe all the characteristic features of BBRVT and discuss its differential. We also discuss the role of ablation for this condition.

Ventricular arrhythmias involving the His-Purkinje system in the structurally abnormal heart

His-Purkinje-related ventricular arrhythmias are a subset of ventricular tachycardias that use the specialized cardiac conduction system. These arrhythmias can occur in various different forms of structural heart disease. Here, we review the basic science discoveries and their analogous clinical observations that implicate the His-Purkinje system as a crucial component of the arrhythmia circuit. While mutations serve the molecular basis for arrhythmias in the heritable cardiomyopathies, transcriptional and posttranslational changes constitute the adverse remodeling leading to arrhythmias in acquired structural heart disease. Additional studies on the electrical properties of the His-Purkinje network and its interactions with the surrounding myocardium will improve the clinical diagnosis and treatment of these arrhythmias.

Atypical Surface ECG Complicating the Diagnosis of Bundle Branch Reentry Tachycardia

BACKGROUND

Typical left bundle branch block (LBBB) during ventricular tachycardia (VT) is a diagnostic criterion of bundle branch reentry tachycardia (BBRT) with activation of the right bundle in the anterograde direction.

METHODS AND RESULTS

Eleven patients (seven male, 60 ± 12 years) with nonischemic cardiomyopathy (left ventricular ejection fraction 37 ± 16%) presenting with BBRT were successfully treated by ablation of the right bundle. Among them, five patients had atypical surface electrocardiograms (ECGs) differing from a typical LBBB during the VT. Three patients with severe enlargement and dysfunction of the left ventricle had broadened irregular QRS complexes with rR or RS configuration in lead V6 during the BBRT. Two patients with enlargement and/or hypokinesia of the right ventricle had entirely or almost entirely negative complexes (QS) in the chest leads (V1-V6) during the VT. Activation mapping in these two patients revealed that the exit site of the BBRT was in the anterior right ventricle generating a negative concordance in the precordial leads.

CONCLUSIONS

Atypical surface ECGs with broadened irregular QRS complexes or negative concordance in the precordial leads can complicate the correct diagnosis of BBRT in patients with severe left ventricular dysfunction and involvement of the right ventricle.

Human His-Purkinje System: Abnormalities of Conduction, Rhythm Disorders and Case Studies

This review covers many of the arrhythmias and conduction abnormalities related to His-Purkinje System. These include junctional premature complexes, junctional and fascicular tachycardias, bundle branch reentry (BBR), and the role of apparent conduction in various forms of supraventricular tachycardias (SVT) with or without involvement of accessory pathways (AP).

Spectrum of Fascicular Arrhythmias

Fascicular arrhythmias encompass a wide spectrum of ventricular arrhythmias that depend on the specialized conduction system of the right and left ventricles. These arrhythmias include premature ventricular complexes, monomorphic ventricular tachycardia, polymorphic ventricular tachycardia, and ventricular fibrillation. These arrhythmias may be organized by mechanism, including intrafascicular reentry, interfascicular reentry, and focal. Mapping and ablation of the fascicular system can result in high cure rates of debilitating and potentially life-threatening arrhythmias. When approaching these arrhythmias, careful consideration of the structure of the His Purkinje system as well as their electrophysiologic properties may help guide even the most complex of arrhythmias.

Mapping and ablation procedures for the treatment of ventricular tachycardia

INTRODUCTION

Ventricular tachycardia (VT) may occur in the presence or absence of structural heart disease. Given that the management of VT hinges on the presence of symptoms and risk of sudden cardiac death (SCD), the main treatment goals are elimination of symptoms (including frequent implantable cardioverter defibrillator [ICD] therapies) and prevention of SCD. Unfortunately, medical management is suboptimal in a significant proportion of patients. As such, ablative therapy plays a prominent role in the treatment of ventricular tachycardia.

AREAS COVERED

In this review, we will discuss various VT disorders that are encountered in patients with and without structural heart disease. Further, we will highlight salient features regarding mapping and ablation of the various VT syndromes. Finally, we will discuss what lies on the horizon for VT ablation. Expert commentary: Meticulous mapping should aim to find the region that is most likely to be successful and least likely to result in a complication. Although recognition of the various mechanisms of VT, familiarity with different methods to mapping and ablation, and awareness of potential limitations of current approaches is critical, a thorough understanding of the fundamental principles and nuances of each facet within EP is required to ensure optimal outcomes for our patients.

The risk of delayed atrioventricular and intraventricular conduction block following ablation of bundle branch reentry

BACKGROUND

The aim of the study was to determine the long-term reliability of atrioventricular and intraventricular conduction and the implications for cardiac resynchronization therapy (CRT-D) following catheter ablation of bundle branch reentry tachycardia (BBRT) and interfascicular tachycardia.

METHODS AND RESULTS

Fourteen patients with recurrent monomorphic ventricular tachycardia (VT) (n = 11) and incessant VT (n = 3) underwent catheter ablation of BBRT (n = 7), interfascicular tachycardia (n = 5) or both arrhythmias (n = 2). Successful ablation was achieved in all patients without intraprocedural atrioventricular (AV) block. Within 2 months after ablation, three patients with BBRT and pre-existing prolonged QRS developed a delayed third-degree AV block. During the follow-up of 2 years, two patients with interfascicular tachycardia developed a new left bundle branch block (LBBB) associated with worsening of heart failure. Three patients underwent upgrading of implantable cardioverter defibrillator therapy to CRT-D early after ablation which improved heart failure during the 6 months follow-up. During the long-term follow-up of 39 ± 13 months, VT storm recurred in one patient. Four of the 14 patients died of deterioration of heart failure and one had to undergo heart transplantation.

CONCLUSIONS

Catheter ablation for BBRT in patients with prolonged QRS is associated with a high risk of delayed third-degree AV block. Ablation of interfascicular tachycardia can be associated with delayed LBBB. After ablation of bundle branch reentry, patients with prolonged QRS are candidates for cardiac resynchronization therapy but the mortality remains high.

Ventricular tachycardia and ventricular fibrillation

Ventricular tachycardia and ventricular fibrillation are the most important causes of sudden cardiac death (SCD), particularly in those with structural heart disease and reduced left ventricular function. It is important to distinguish ventricular tachycardia from supraventricular tachycardia. A wide spectrum of ventricular arrhythmias exists, from those where the heart is structurally normal to those with structural heart disease. Each entity has a distinctive pathophysiology, treatment plan and prognostic outcome. Treatment modalities include simple beta-blockade to implantation of implantable cardiac defibrillator and ablative approaches. In general, those ventricular arrhythmias associated with a structurally normal heart are more benign than those associated with structural heart disease.

Incessant interfascicular reentrant ventricular tachycardia as a result of catheter ablation of the right bundle branch: case report and review of the literature

A 72-year-old woman developed incessant interfascicular (IF) ventricular tachycardia immediately after successful right bundle branch (RBB) catheter ablation for the treatment of sustained bundle branch reentrant tachycardia. Catheter ablation of the left bundle branch and the left anterior fascicle was successful in eliminating the tachycardia (in 2 different sessions). This report discusses the direct link between the creation of an RBB block and the development of IF tachycardia, in our case, and in prior cases of IF reentry reported in the literature.

Ventricular tachycardia and sudden cardiac death

Ventricular tachycardia (VT), which most commonly occurs in patients with structural heart disease, can be associated with an increased risk of sudden death. The most common cause of ventricular fibrillation is acute coronary ischemia, whereas a myocardial scar from prior infarct is the most common cause of sustained monomorphic VT in patients with structural heart disease. More benign forms of idiopathic VT can also occur in the absence of structural heart disease. Treatment of VT involves both emergent management and prevention of recurrence with medical and device therapy. Appropriately selected patients who have experienced VT or those who are at risk of VT may be candidates for an implantable cardioverter-defibrillator. The left ventricular ejection fraction is most frequently used to stratify patients with either ischemic or nonischemic cardiomyopathy who are at risk of sudden death and may be candidates for a prophylactic defibrillator. Catheter ablation may also be an option for appropriately selected patients with many forms of VT. This article discusses the etiologies and management of VT and its association with sudden death.

Ventricular tachycardia and sudden cardiac death

Ventricular tachycardia (VT), which most commonly occurs in patients with structural heart disease, can be associated with an increased risk of sudden death. The most common cause of ventricular fibrillation is acute coronary ischemia, whereas a myocardial scar from prior infarct is the most common cause of sustained monomorphic VT in patients with structural heart disease. More benign forms of idiopathic VT can also occur in the absence of structural heart disease. Treatment of VT involves both emergent management and prevention of recurrence with medical and device therapy. Appropriately selected patients who have experienced VT or those who are at risk of VT may be candidates for an implantable cardioverter-defibrillator. The left ventricular ejection fraction is most frequently used to stratify patients with either ischemic or nonischemic cardiomyopathy who are at risk of sudden death and may be candidates for a prophylactic defibrillator. Catheter ablation may also be an option for appropriately selected patients with many forms of VT. This article discusses the etiologies and management of VT and its association with sudden death.

Ventricular Tachycardia With Participation of the Left Bundle-Purkinje System in Patients With Structural Heart Disease: Identification of Slow Conduction During Sinus Rhythm

INTRODUCTION

Idiopathic left ventricular tachycardia (VT) originating from the left posterior fascicle can be eliminated by ablation at sites with abnormal diastolic potentials (DPs) during sinus rhythm. We investigated whether such DPs can also be recorded in patients with structural heart disease and VT involving the left bundle-Purkinje system.

METHODS AND RESULTS

Eight patients (mean age 67 +/- 11 years) with nonischemic cardiomyopathy (n = 5) or prior myocardial infarction (n = 3) presented with VT involving the left bundle-Purkinje system (cycle length 376 +/- 45 ms). Three types of VT were observed: macroreentrant VT with participation of both left bundle fascicles in three patients, fascicular VT involving the left posterior fascicle in two patients, and scar-related VT with Purkinje fibers as part of the reentrant circuit in three patients. In all patients, abnormal isolated DPs of low amplitude with a QRS-earliest DP interval of 374 +/- 86 ms were found during sinus rhythm in the mid- or inferior left ventricular septum in areas with Purkinje potentials. The abnormal DPs during sinus rhythm coincided or were in proximity to DPs during the VT in six patients. VT ablation targeting the sites with the earliest abnormal DPs during sinus eliminated the VT in 7 of 8 patients with freedom from VT recurrence in six patients during the follow-up of 11 +/- 5 months.

CONCLUSIONS

Isolated DPs during sinus rhythm were found in proximity to the posterior Purkinje network in patients with VT involving the left bundle-Purkinje system associated with heart disease and can be used to guide successful catheter ablation.