Strategies to Reduce Recurrent Shocks Due to Ventricular Arrhythmias in Patients with an Implanted Cardioverter-Defibrillator

Factors associated with implantable cardioverter-defibrillator shocks in patients suffering from non-ischemic cardiomyopathy

BACKGROUND

Although intra-cardiac shocks are a lifesaving approach in patients with systolic heart failure (HF), the probable effective factors related to shock occurrence are less frequently recognized. We designed this study to assess the factors associated with inappropriate or appropriate implantable cardioverter-defibrillator (ICD) shocks in patients with non-ischemic cardiomyopathy (NICM).

METHODS

Ninety-nine patients with NICM who implanted ICD were enrolled from March 2018 to September 2019 and followed up with a three-month interval for up to one year. Shock therapy was defined as either appropriate or inappropriate shock. The odds ratio (OR) of inappropriate shock occurrence was calculated with crude and different adjusted models.

RESULTS

The mean age of the population at baseline was 51.9 ± 15.4 years (men: 71%). Baseline data revealed that patients with inappropriate shocks had higher heart rates (HR), worse New York Heart Association (NYHA) class, and anti-tachycardia pacing (ATP) as well as higher percentages of amiodarone usage compared to groups with appropriate or no shock [HR: 96.8 ± 27.8 vs. 79.8 ± 12.1 vs. 76.2 ± 17.6 beats per minute (bpm), P = 0.014; NYHA class IV: 85.7% vs. 74.1% vs. 63.4%, P = 0.041; ATP: 37.5% vs. 29% vs. 5%, P = 0.010; amiodarone usage: 37.5% vs. 25.8% vs. 5%, P = 0.23, respectively]. Further multiple-adjusted OR did not reveal any significant independent association between the aforementioned variables and inappropriate shock incidence.

CONCLUSION

This study indicates no significant independent predisposing factor in the occurrence of inappropriate shocks among patients with NICM. Other studies are required in this regard.

The efficacy of catheter ablation versus ICD for prevention of ventricular tachycardia in patients with ischemic heart disease: a systematic review and meta-analysis

Purpose

Although implantable cardioverter defibrillator (ICD) could prevent the sudden death of ventricular tachycardia (VT) in patients with ischemic heart disease, it could not effectively prevent the recurrence of ventricular tachycardia. Several studies have suggested that catheter ablation may effectively decrease the incidence of ICD events, but relevant dates from randomized controlled trials were limited.

Methods

A systematic review and meta-analysis of randomized controlled trials were performed to evaluate the effect of catheter ablation for the prevention of VT in patients with ischemic heart disease. Random-effects model with inverse-variance weighting method was used to pool odds ratios. Egger method was performed to evaluate whether there was public bias in each outcome.

Results

Four studies enrolling a total of 605 patients were included in the present meta-analysis. Compared with the control group (ICD ± AAD), catheter ablation could significantly reduce the incidence of ICD therapy (OR, 0.49; 95% CI, 0.28 ~ 0.87), ICD shock (OR, 0.50; 95% CI, 0.28 ~ 0.87), VT storm (OR, 0.60; 95% CI, 0.40 ~ 0.90), and cardiovascular-related hospitalization (OR, 0.66; 95% CI, 0.45 ~ 0.9). But there was no significant difference among the risk of all-cause mortality (OR, 0.89; 95% CI, 0.59 ~ 1.34), cardiovascular mortality (OR, 0.76; 95% CI, 0.44 ~ 1.30), and complication (OR, 0.89; 95% CI, 0.30 ~ 2.67).

Conclusion

These results showed that catheter ablation combined with ICD could reduce ICD therapy, ICD shock, and VT storm in patients with ischemic heart disease, but there was no improvement in all-cause mortality. Meanwhile, it also provided a basic guidance for the design of larger clinical randomized trials with longer follow-up in the future.

Electronic supplementary material

The online version of this article (10.1007/s10840-020-00848-1) contains supplementary material, which is available to authorized users.

Comparable risk of recurrent ventricular tachyarrhythmias in implantable cardioverter-defibrillator recipients treated with single beta-blocker or combined amiodarone

This study sought to assess the prognostic impact of treatment with single beta-blocker (BB) compared to combined therapy with BB plus amiodarone (BB-AMIO) on recurrences of ventricular tachyarrhythmias in implantable cardioverter-defibrillator (ICD) recipients. A large retrospective registry was used including consecutive ICD recipients with index episodes of ventricular tachyarrhythmias from 2002 to 2016. Patients treated with BB were compared to patients treated with BB-AMIO. Kaplan-Meier and Cox regression analyses were applied for the evaluation of the primary end-point defined as first recurrences of ventricular tachyarrhythmias at five years. Secondary end-points comprised first appropriate ICD therapies, first cardiac rehospitalization and all-cause mortality at five years. Among 512 ICD recipients, 81% were treated with BB and 19% with BB-AMIO. BB and BB-AMIO were associated with comparable risk of first recurrences of ventricular tachyarrhythmias (46% vs. 43%; log rank P = .941; HR = 1.013; 95% CI 0.725-1.415; P = .941) and appropriate ICD therapies (35% vs. 37%; log rank P = .389; HR = 0.852; 95% CI 0.591-1.228; P = .390). BB was associated with decreased long-term all-cause mortality within an univariable analysis only (20% vs. 28%; log rank p = 0.023). In conclusion, BB and BB-AMIO were associated with comparable risks regarding recurrences of ventricular tachyarrhythmias at five years.