Meta-Analysis of Clinical Outcome After Implantable Cardioverter-Defibrillator Implantation in Patients With Brugada Syndrome

OBJECTIVES

This study sought to summarize the clinical outcome of implantable cardioverter-defibrillator (ICD) therapy in patients with Brugada syndrome.

BACKGROUND

Brugada syndrome is characterized by cardiac conduction abnormalities and a high risk of ventricular arrhythmias that may result in sudden cardiac death. A complete overview of clinical outcome, appropriate and inappropriate interventions, and complications after ICD therapy in patients with Brugada syndrome is lacking.

METHODS

The online MEDLINE database was searched for published reports and yielded 828 studies on outcome and complications after ICD therapy in patients with Brugada syndrome. After careful evaluation, 22 studies including a total of 1,539 patients were included in the meta-analysis.

RESULTS

In total, 1,539 patients (mean age 45 years, 18% women) underwent ICD implantation for primary (79%) or secondary (21%) prevention of sudden cardiac death. During a mean follow-up of 4.9 years, the appropriate and inappropriate ICD intervention rates were 3.1 and 3.3 per 100 person-years, respectively. The cardiac mortality rate was 0.03 per 100 person-years and noncardiac mortality rate was 0.3 per 100 person-years. ICD-related complications per 100 person-years consisted of lead malfunction (1.6), psychological complication (1.3), infection (0.6), lead dislocation (0.4), and any complication (0.6).

CONCLUSIONS

Patients with Brugada syndrome judged to be at high risk for ventricular arrhythmia may significantly benefit from ICD therapy, which is associated with an appropriate ICD intervention rate of 3.1 per 100 person-years and low cardiac and noncardiac mortality rates. Inappropriate ICD interventions and ICD-related complications may lead to considerable morbidity.

T Wave Safety Margin during the Process of ICD Implantation As a Novel Predictor of T Wave Oversensing

Introduction: T wave oversensing (TWOS) is a major drawback of implantable cardioverter defibrillator (ICD) and data on predictors of TWOS in ICD is limited. We aimed to calculate a novel index of T wave safety margin (TWSM) and assess its potential for evaluating TWOS during the procedure of ICD implantation. Methods and Results: Thirty-two consecutive patients with ICD implantation were enrolled. During each procedure of ICD implantation, different ICD generators were connected to implanted sensing lead through active-fixation leads and bridging cables. R and T wave amplitudes were measured on ICD printouts according to the gain. The ICDs were programed to the most sensitive settings to reveal possible TWOS. A novel index TWSM was calculated according to the corresponding sensing algorithm of ICD. There was discrepancy of R wave amplitudes measured by different ICDs (P < 0.01). In Fortify and Teligen ICDs, T wave amplitudes showed no difference (P > 0.05) and TWSMs were sufficiently high (post sensing: 13.0 ± 7.6 and 28.3 ± 16.5, respectively, post pacing: 5.0 ± 2.2 and 4.6 ± 0.9, respectively). In nine patients with 10 TWOS episodes detected during the procedure of ICD implantation, generators with the highest TWSM were chosen. Only one TWOS episode during pacing was recorded during the 25 ± 7 mo follow-up period. Conclusions: We first propose the index of TWSM during ICD implantation as a potentially efficient predictor for TWOS. Evaluation of TWSM might help to reduce TWOS episodes in patients with high risk of TWOS. Prospective studies are warranted to validate this index and its potential to reduce TWOS episodes.

Development of ventricular fibrillation after implantation of a biventricular implantable cardioverter defibrillator: what is the mechanism?

Syncopal spells in heart failure patient with cardiovascular implantable electronic devices (CIED) require multiple assessments. T‐wave oversensing is a well‐described phenomenon that remains significant in modern implantable cardioverter defibrillators (ICD) systems. It can lead to inappropriate therapies and loss of biventricular pacing in those with cardiac resynchronization devices. Strategies to overcome this problem are important.