A comparison of left bundle branch pacing with His bundle pacing in a patient with heart failure and left bundle branch block.

Feasibility and efficacy of left bundle branch area pacing in patients indicated for cardiac resynchronization therapy.

AIMS:The present study was to evaluate the feasibility and clinical outcomes of left bundle branch area pacing (LBBAP) in cardiac resynchronization therapy (CRT)-indicated patients.METHODS AND RESULTS:LBBAP was performed via transventricular septal approach in 25 patients as a rescue strategy in 5 patients with failed left ventricular (LV) lead placement and as a primary strategy in the remaining 20 patients. Pacing parameters, procedural characteristics, electrocardiographic, and echocardiographic data were assessed at implantation and follow-up. Of 25 enrolled CRT-indicated patients, 14 had left bundle branch block (LBBB, 56.0%), 3 right bundle branch block (RBBB, 12.0%), 4 intraventricular conduction delay (IVCD, 16.0%), and 4 ventricular pacing dependence (16.0%). The QRS duration (QRSd) was significantly shortened by LBBAP (intrinsic 163.6 ± 29.4 ms vs. LBBAP 123.0 ± 10.8 ms, P < 0.001). During the mean follow-up of 9.1 months, New York Heart Association functional class was improved to 1.4 ± 0.6 from baseline 2.6 ± 0.6 (P < 0.001), left ventricular ejection fraction (LVEF) increased to 46.9 ± 10.2% from baseline 35.2 ± 7.0% (P < 0.001), and LV end-diastolic dimensions (LVEDD) decreased to 56.8 ± 9.7 mm from baseline 64.1 ± 9.9 mm (P < 0.001). There was a significant improvement (34.1 ± 7.4% vs. 50.0 ± 12.2%, P < 0.001) in LVEF in patients with LBBB.CONCLUSION:The present study demonstrates the clinical feasibility of LBBAP in CRT-indicated patients. Left bundle branch area pacing generated narrow QRSd and led to reversal remodelling of LV with improvement in cardiac function. LBBAP may be an alternative to CRT in patients with failure of LV lead placement and a first-line option in selected patients such as those with LBBB and heart failure.

Bilateral Bundle Branch Area Pacing to Achieve Physiological Conduction System Activation.

BACKGROUND:Left bundle branch pacing (LBBP) is a technique for conduction system pacing, but it often results in right bundle branch block morphology on the ECG. This study was designed to assess simultaneous pacing of the left and right bundle branch areas to achieve more synchronous ventricular activation.METHODS:In symptomatic bradycardia patients, the distal electrode of a bipolar pacing lead was placed at the left bundle branch area via a transventricular-septal approach. This was used to pace the left bundle branch area, while the ring electrode was used to pace the right bundle branch area. Bilateral bundle branch area pacing (BBBP) was achieved by stimulating the cathode and anode in various pacing configurations. QRS duration, delayed right ventricular activation time, left ventricular activation time, and interventricular conduction delay were measured. Pacing stability and short-term safety were assessed at 3-month follow-up.RESULTS:BBBP was successfully performed in 22 of 36 patients. Compared with LBBP, BBBP resulted in greater shortening of QRS duration (109.3±7.1 versus 118.4±5.7 ms, P<0.001). LBBP resulted in a paced right bundle branch block configuration, with a delayed right ventricular activation time of 115.0±7.5 ms and interventricular conduction delay of 34.0±8.8 ms. BBBP fully resolved the right bundle branch block morphology in 18 patients. In the remaining 4 patients, BBBP partially corrected the right bundle branch block with delayed right ventricular activation time decreasing from 120.5±4.7 ms during LBBP to 106.1±4.2 ms during BBBP (P=0.005).CONCLUSIONS:LBBP results in a relatively narrow QRS complex but with an interventricular activation delay. BBBP can diminish the delayed right ventricular activation, producing more physiological ventricular activation. Graphic Abstract: A graphic abstract is available for this article.

Left bundle branch pacing for symptomatic bradycardia: Implant success rate, safety, and pacing characteristics.

BACKGROUND:In patients with or without left bundle branch block, left bundle branch pacing (LBBP) can produce near normalization of QRS duration (QRSd). This has recently emerged as an alternative technique to His bundle pacing.OBJECTIVES:The purpose of this study was to characterize a novel approach for LBBP in patients with bradycardia indications for pacing and to assess implant success rate and midterm safety.METHODS:Patients with bradycardia indications for pacing underwent LBBP by a trans-ventricular-septal method in the basal ventricular septum. Procedural success, pacing parameters, and complications were assessed at implantation and at 3 months follow-up.RESULTS:This prospective study evaluated 87 patients (sinus node dysfunction 67.8%; atrioventricular conduction disease 32.2%) undergoing pacemaker implantation. LBBP implantation succeeded in 80.5% (70/87) of patients and the remaining 17 patients received right ventricular septal pacing. The procedure time of LBBP implantation was 18.0 ± 8.8 minutes with a fluoroscopic exposure time of 3.9 ± 2.7 minutes. LBBP produced narrower electrocardiographic QRSd than did right ventricular septal pacing (113.2 ± 9.9 ms vs 144.4 ± 12.8 ms; P < .001). There were no major implantation-related complications. The pacing threshold was low (0.76 ± 0.22 V at implantation and 0.71 ± 0.23 V at 3 months), with no loss of capture or lead dislodgment observed.CONCLUSION:This study demonstrates that in patients with standard bradycardia pacing indications, LBBP results in QRSd < 120 ms in most patients and can be performed successfully and safely in the majority of patients.

Heart rate-adjusted PR as a prognostic marker of long-term ventricular arrhythmias and cardiac death in ICD/CRT-D recipients.

OBJECTIVE:To evaluate the PR to RR interval ratio (PR/RR, heart rate-adjusted PR) as a prognostic marker for long-term ventricular arrhythmias and cardiac death in patients with implantable cardioverter defibrillator (ICDs) and cardiac resynchronization therapy with defibrillators (CRT-D).METHODS:We retrospectively analyzed data from 428 patients who had an ICD/CRT-D equipped with home monitoring. Baseline PR and RR interval data prior to ICD/CRT-D implantation were collected from standard 12-lead electrocardiograph, and the PR/RR was calculated. The primary endpoint was appropriate ICD/CRT-D treatment of ventricular arrhythmias (VAs), and the secondary endpoint was cardiac death.RESULTS:During a mean follow-up period of 38.8 ± 10.6 months, 197 patients (46%) experienced VAs, and 47 patients (11%) experienced cardiac death. The overall PR interval was 160 ± 40 ms, and the RR interval was 866 ± 124 ms. Based on the receiver operating characteristic curve, a cut-off value of 18.5% for the PR/RR was identified to predict VAs. A PR/RR ≥ 18.5% was associated with an increased risk of VAs [hazard ratio (HR) = 2.243, 95% confidence interval (CI) = 1.665-3.022, P < 0.001) and cardiac death (HR = 2.358, 95%CI = 1.240-4.483, P = 0.009) in an unadjusted analysis. After adjustment in a multivariate Cox model, the relationship remained significant among PR/RR ≥ 18.5%, VAs (HR = 2.230, 95%CI = 1.555-2.825, P < 0.001) and cardiac death (HR = 2.105, 95%CI = 1.101-4.025, P = 0.024.CONCLUSIONS:A PR/RR ≥ 18.5% at baseline can serve as a predictor of future VAs and cardiac death in ICD/CRT-D recipients.

Recovery of complete left bundle branch block following heart failure improvement by left bundle branch pacing in a patient.

A 57-year-old male presented with symptomatic systolic heart failure and complete left bundle branch block (LBBB). Left bundle branch pacing corrected LBBB at a low capture threshold (0.5V @0.4ms) with right bundle branch conduction delay and paced QRS morphology changed to near-normal by adjusting AV delay with diminished RBBD. At 1-year follow-up, the patient had a significant improvement in heart failure and LBBB automatically resolved with a rate-dependent pattern. LBBP may be an alternative to conventional cardiac resynchronization therapy with the likelihood of recovery of LBBB. More research is needed to evaluate the potential use of this pacing strategy in patients with LBBB and heart failure.

Comparison of electrocardiogram characteristics and pacing parameters between left bundle branch pacing and right ventricular pacing in patients receiving pacemaker therapy.

AIMS:This study explores the feasibility of left bundle branch pacing (LBBP) and characterizes electrocardiogram (ECG) patterns during the pacing in comparison with conventional right ventricular pacing (RVP).METHODS AND RESULTS:Forty pacing-indicated patients were prospectively enrolled. Twenty patients underwent LBBP (the LBBP group), and 20 patients underwent RVP (the RVP group). Left bundle branch pacing was achieved by transseptal method in the basal ventricular septum. Electrocardiogram characteristics, pacing parameters, pacing sites, and safety events were assessed at implantation and 3-month follow-up. In the LBBP group, the pacing lead was successfully placed near the endocardium of the left side of the septum. Electrocardiogram pattern during LBBP showed right bundle branch conduction delay. Left bundle branch block (LBBB) in two patients was corrected by LBBP. Post-implantation 3D echocardiography confirmed the pacing location. In the RVP group, ECG showed LBBB pattern. The paced QRS duration was 111.85 ± 10.77 ms in LBBP group and 160.15 ± 15.04 ms in the RVP group (P < 0.001). Pacing thresholds (at implantation: 0.73 ± 0.20 V in the LBBP group and 0.61 ± 0.23 V in the RVP group) remained low and stable at 3-month follow-up. No adverse event was observed during 3-month follow-up.CONCLUSION:This study demonstrates the clinical feasibility of LBBP. Left bundle branch pacing that has a low pacing threshold and produces narrow ECG QRS duration may be a new pacing strategy for patients in need of ventricular pacing.

How to implant left bundle branch pacing lead in routine clinical practice.

INTRODUCTION:Left bundle branch pacing (LBBP) is characterized with a low and stable pacing capture threshold, relatively narrow QRS duration due to fast left ventricular activation, and direct excitation of the diseased left bundle branch. This report aims to describe the methods, procedural skills, and clinical implications of performing LBBP implantation.METHODS AND RESULTS:LBBP is achieved by transventricular-septal approach. There are two methods to identify the location for LBBP lead placement: the single-lead method and the dual-lead method. During implantation, the unique transition of the paced QRS morphology and pacing parameter changes are important for guiding the lead - advancement to the left side of the interventricular septum. In our experience, LBBP can be safely performed in most patients requiring pacemaker therapy.CONCLUSION:Clinical development of LBBP is at an early but encouraging phase with increasing clinical use, and a standardized procedure with improved delivery tools and pacing leads is needed, as well as long-term efficacy and safety.

Retraction notice to "Association of angiotensin II receptor 1 and lectin-like oxidized low-density lipoprotein receptor-1 mediates the cardiac hypertrophy induced by oxidized low-density lipoprotein" [Biochem. Biophys. Res. Commun. 490 (1) (2017) 55-61].

Long-term follow-up of arrhythmogenic right ventricular cardiomyopathy patients with an implantable cardioverter-defibrillator for prevention of sudden cardiac death.

BACKGROUND:Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a rare inherited cardiomyopathy with a high burden of ventricular arrhythmia, which is an important cause of sudden cardiac death (SCD). Implantable cardioverter-defibrillator (ICD) is believed to be the most reliable management against SCD.HYPOTHESIS:Ventricular arrhythmia does not necessarily confer a poor prognosis in ARVC patients with an ICD.METHODS:A total of 39 ARVC patients (34 male) implanted with an ICD at our electrophysiology center and followed up continuously were included in this study. The mean age at diagnosis was 42.1 ± 14.8 years.RESULTS:Thirty-three patients (84.6%) had suffered ventricular arrhythmia with hemodynamic compromise before ICD implantation. During a median follow-up of 48.6 months (interquartile range, 32.3-73.3), 3 patients (7.7%) died, 1 of sudden death, 1 of heart failure, and 1 of cerebral infarction. Twenty-eight patients (71.8%) experienced 540 appropriate ICD interventions. The first appropriate ICD intervention occurred more than 2 years after initial ICD implantation in 5 patients (12.8%). Twelve patients (30.8%) suffered from electrical storm. The event-free period was significantly shorter in patients who did not have broad precordial T wave inversion ≥V1-V3 (hazard ratio = 0.39, 95% confidence interval: 0.16-0.96). No significant difference was shown in antiarrhythmic drugs and radiofrequency catheter ablation before ICD implantation between patients with and without appropriate ICD therapies (P > 0.05).CONCLUSIONS:Recurrence of sustained ventricular tachycardia/ventricular fibrillation is frequent in high-risk patients with ARVC. The prognosis is favorable for ARVC patients treated with an ICD for prevention of SCD.

A comparison of left bundle branch pacing with His bundle pacing in a patient with heart failure and left bundle branch block.

Feasibility and efficacy of left bundle branch area pacing in patients indicated for cardiac resynchronization therapy.

AIMS:The present study was to evaluate the feasibility and clinical outcomes of left bundle branch area pacing (LBBAP) in cardiac resynchronization therapy (CRT)-indicated patients.METHODS AND RESULTS:LBBAP was performed via transventricular septal approach in 25 patients as a rescue strategy in 5 patients with failed left ventricular (LV) lead placement and as a primary strategy in the remaining 20 patients. Pacing parameters, procedural characteristics, electrocardiographic, and echocardiographic data were assessed at implantation and follow-up. Of 25 enrolled CRT-indicated patients, 14 had left bundle branch block (LBBB, 56.0%), 3 right bundle branch block (RBBB, 12.0%), 4 intraventricular conduction delay (IVCD, 16.0%), and 4 ventricular pacing dependence (16.0%). The QRS duration (QRSd) was significantly shortened by LBBAP (intrinsic 163.6 ± 29.4 ms vs. LBBAP 123.0 ± 10.8 ms, P < 0.001). During the mean follow-up of 9.1 months, New York Heart Association functional class was improved to 1.4 ± 0.6 from baseline 2.6 ± 0.6 (P < 0.001), left ventricular ejection fraction (LVEF) increased to 46.9 ± 10.2% from baseline 35.2 ± 7.0% (P < 0.001), and LV end-diastolic dimensions (LVEDD) decreased to 56.8 ± 9.7 mm from baseline 64.1 ± 9.9 mm (P < 0.001). There was a significant improvement (34.1 ± 7.4% vs. 50.0 ± 12.2%, P < 0.001) in LVEF in patients with LBBB.CONCLUSION:The present study demonstrates the clinical feasibility of LBBAP in CRT-indicated patients. Left bundle branch area pacing generated narrow QRSd and led to reversal remodelling of LV with improvement in cardiac function. LBBAP may be an alternative to CRT in patients with failure of LV lead placement and a first-line option in selected patients such as those with LBBB and heart failure.

Bilateral Bundle Branch Area Pacing to Achieve Physiological Conduction System Activation.

BACKGROUND:Left bundle branch pacing (LBBP) is a technique for conduction system pacing, but it often results in right bundle branch block morphology on the ECG. This study was designed to assess simultaneous pacing of the left and right bundle branch areas to achieve more synchronous ventricular activation.METHODS:In symptomatic bradycardia patients, the distal electrode of a bipolar pacing lead was placed at the left bundle branch area via a transventricular-septal approach. This was used to pace the left bundle branch area, while the ring electrode was used to pace the right bundle branch area. Bilateral bundle branch area pacing (BBBP) was achieved by stimulating the cathode and anode in various pacing configurations. QRS duration, delayed right ventricular activation time, left ventricular activation time, and interventricular conduction delay were measured. Pacing stability and short-term safety were assessed at 3-month follow-up.RESULTS:BBBP was successfully performed in 22 of 36 patients. Compared with LBBP, BBBP resulted in greater shortening of QRS duration (109.3±7.1 versus 118.4±5.7 ms, P<0.001). LBBP resulted in a paced right bundle branch block configuration, with a delayed right ventricular activation time of 115.0±7.5 ms and interventricular conduction delay of 34.0±8.8 ms. BBBP fully resolved the right bundle branch block morphology in 18 patients. In the remaining 4 patients, BBBP partially corrected the right bundle branch block with delayed right ventricular activation time decreasing from 120.5±4.7 ms during LBBP to 106.1±4.2 ms during BBBP (P=0.005).CONCLUSIONS:LBBP results in a relatively narrow QRS complex but with an interventricular activation delay. BBBP can diminish the delayed right ventricular activation, producing more physiological ventricular activation. Graphic Abstract: A graphic abstract is available for this article.

Left bundle branch pacing for symptomatic bradycardia: Implant success rate, safety, and pacing characteristics.

BACKGROUND:In patients with or without left bundle branch block, left bundle branch pacing (LBBP) can produce near normalization of QRS duration (QRSd). This has recently emerged as an alternative technique to His bundle pacing.OBJECTIVES:The purpose of this study was to characterize a novel approach for LBBP in patients with bradycardia indications for pacing and to assess implant success rate and midterm safety.METHODS:Patients with bradycardia indications for pacing underwent LBBP by a trans-ventricular-septal method in the basal ventricular septum. Procedural success, pacing parameters, and complications were assessed at implantation and at 3 months follow-up.RESULTS:This prospective study evaluated 87 patients (sinus node dysfunction 67.8%; atrioventricular conduction disease 32.2%) undergoing pacemaker implantation. LBBP implantation succeeded in 80.5% (70/87) of patients and the remaining 17 patients received right ventricular septal pacing. The procedure time of LBBP implantation was 18.0 ± 8.8 minutes with a fluoroscopic exposure time of 3.9 ± 2.7 minutes. LBBP produced narrower electrocardiographic QRSd than did right ventricular septal pacing (113.2 ± 9.9 ms vs 144.4 ± 12.8 ms; P < .001). There were no major implantation-related complications. The pacing threshold was low (0.76 ± 0.22 V at implantation and 0.71 ± 0.23 V at 3 months), with no loss of capture or lead dislodgment observed.CONCLUSION:This study demonstrates that in patients with standard bradycardia pacing indications, LBBP results in QRSd < 120 ms in most patients and can be performed successfully and safely in the majority of patients.

Heart rate-adjusted PR as a prognostic marker of long-term ventricular arrhythmias and cardiac death in ICD/CRT-D recipients.

OBJECTIVE:To evaluate the PR to RR interval ratio (PR/RR, heart rate-adjusted PR) as a prognostic marker for long-term ventricular arrhythmias and cardiac death in patients with implantable cardioverter defibrillator (ICDs) and cardiac resynchronization therapy with defibrillators (CRT-D).METHODS:We retrospectively analyzed data from 428 patients who had an ICD/CRT-D equipped with home monitoring. Baseline PR and RR interval data prior to ICD/CRT-D implantation were collected from standard 12-lead electrocardiograph, and the PR/RR was calculated. The primary endpoint was appropriate ICD/CRT-D treatment of ventricular arrhythmias (VAs), and the secondary endpoint was cardiac death.RESULTS:During a mean follow-up period of 38.8 ± 10.6 months, 197 patients (46%) experienced VAs, and 47 patients (11%) experienced cardiac death. The overall PR interval was 160 ± 40 ms, and the RR interval was 866 ± 124 ms. Based on the receiver operating characteristic curve, a cut-off value of 18.5% for the PR/RR was identified to predict VAs. A PR/RR ≥ 18.5% was associated with an increased risk of VAs [hazard ratio (HR) = 2.243, 95% confidence interval (CI) = 1.665-3.022, P < 0.001) and cardiac death (HR = 2.358, 95%CI = 1.240-4.483, P = 0.009) in an unadjusted analysis. After adjustment in a multivariate Cox model, the relationship remained significant among PR/RR ≥ 18.5%, VAs (HR = 2.230, 95%CI = 1.555-2.825, P < 0.001) and cardiac death (HR = 2.105, 95%CI = 1.101-4.025, P = 0.024.CONCLUSIONS:A PR/RR ≥ 18.5% at baseline can serve as a predictor of future VAs and cardiac death in ICD/CRT-D recipients.

Recovery of complete left bundle branch block following heart failure improvement by left bundle branch pacing in a patient.

A 57-year-old male presented with symptomatic systolic heart failure and complete left bundle branch block (LBBB). Left bundle branch pacing corrected LBBB at a low capture threshold (0.5V @0.4ms) with right bundle branch conduction delay and paced QRS morphology changed to near-normal by adjusting AV delay with diminished RBBD. At 1-year follow-up, the patient had a significant improvement in heart failure and LBBB automatically resolved with a rate-dependent pattern. LBBP may be an alternative to conventional cardiac resynchronization therapy with the likelihood of recovery of LBBB. More research is needed to evaluate the potential use of this pacing strategy in patients with LBBB and heart failure.

Comparison of electrocardiogram characteristics and pacing parameters between left bundle branch pacing and right ventricular pacing in patients receiving pacemaker therapy.

AIMS:This study explores the feasibility of left bundle branch pacing (LBBP) and characterizes electrocardiogram (ECG) patterns during the pacing in comparison with conventional right ventricular pacing (RVP).METHODS AND RESULTS:Forty pacing-indicated patients were prospectively enrolled. Twenty patients underwent LBBP (the LBBP group), and 20 patients underwent RVP (the RVP group). Left bundle branch pacing was achieved by transseptal method in the basal ventricular septum. Electrocardiogram characteristics, pacing parameters, pacing sites, and safety events were assessed at implantation and 3-month follow-up. In the LBBP group, the pacing lead was successfully placed near the endocardium of the left side of the septum. Electrocardiogram pattern during LBBP showed right bundle branch conduction delay. Left bundle branch block (LBBB) in two patients was corrected by LBBP. Post-implantation 3D echocardiography confirmed the pacing location. In the RVP group, ECG showed LBBB pattern. The paced QRS duration was 111.85 ± 10.77 ms in LBBP group and 160.15 ± 15.04 ms in the RVP group (P < 0.001). Pacing thresholds (at implantation: 0.73 ± 0.20 V in the LBBP group and 0.61 ± 0.23 V in the RVP group) remained low and stable at 3-month follow-up. No adverse event was observed during 3-month follow-up.CONCLUSION:This study demonstrates the clinical feasibility of LBBP. Left bundle branch pacing that has a low pacing threshold and produces narrow ECG QRS duration may be a new pacing strategy for patients in need of ventricular pacing.

How to implant left bundle branch pacing lead in routine clinical practice.

INTRODUCTION:Left bundle branch pacing (LBBP) is characterized with a low and stable pacing capture threshold, relatively narrow QRS duration due to fast left ventricular activation, and direct excitation of the diseased left bundle branch. This report aims to describe the methods, procedural skills, and clinical implications of performing LBBP implantation.METHODS AND RESULTS:LBBP is achieved by transventricular-septal approach. There are two methods to identify the location for LBBP lead placement: the single-lead method and the dual-lead method. During implantation, the unique transition of the paced QRS morphology and pacing parameter changes are important for guiding the lead - advancement to the left side of the interventricular septum. In our experience, LBBP can be safely performed in most patients requiring pacemaker therapy.CONCLUSION:Clinical development of LBBP is at an early but encouraging phase with increasing clinical use, and a standardized procedure with improved delivery tools and pacing leads is needed, as well as long-term efficacy and safety.

Retraction notice to "Association of angiotensin II receptor 1 and lectin-like oxidized low-density lipoprotein receptor-1 mediates the cardiac hypertrophy induced by oxidized low-density lipoprotein" [Biochem. Biophys. Res. Commun. 490 (1) (2017) 55-61].

Long-term follow-up of arrhythmogenic right ventricular cardiomyopathy patients with an implantable cardioverter-defibrillator for prevention of sudden cardiac death.

BACKGROUND:Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a rare inherited cardiomyopathy with a high burden of ventricular arrhythmia, which is an important cause of sudden cardiac death (SCD). Implantable cardioverter-defibrillator (ICD) is believed to be the most reliable management against SCD.HYPOTHESIS:Ventricular arrhythmia does not necessarily confer a poor prognosis in ARVC patients with an ICD.METHODS:A total of 39 ARVC patients (34 male) implanted with an ICD at our electrophysiology center and followed up continuously were included in this study. The mean age at diagnosis was 42.1 ± 14.8 years.RESULTS:Thirty-three patients (84.6%) had suffered ventricular arrhythmia with hemodynamic compromise before ICD implantation. During a median follow-up of 48.6 months (interquartile range, 32.3-73.3), 3 patients (7.7%) died, 1 of sudden death, 1 of heart failure, and 1 of cerebral infarction. Twenty-eight patients (71.8%) experienced 540 appropriate ICD interventions. The first appropriate ICD intervention occurred more than 2 years after initial ICD implantation in 5 patients (12.8%). Twelve patients (30.8%) suffered from electrical storm. The event-free period was significantly shorter in patients who did not have broad precordial T wave inversion ≥V1-V3 (hazard ratio = 0.39, 95% confidence interval: 0.16-0.96). No significant difference was shown in antiarrhythmic drugs and radiofrequency catheter ablation before ICD implantation between patients with and without appropriate ICD therapies (P > 0.05).CONCLUSIONS:Recurrence of sustained ventricular tachycardia/ventricular fibrillation is frequent in high-risk patients with ARVC. The prognosis is favorable for ARVC patients treated with an ICD for prevention of SCD.