Implantable cardioverter defibrillator use in arrhythmogenic right ventricular cardiomyopathy in North America and Europe

Abstract

Background and aims: Implantable cardioverter-defibrillators (ICDs) are critical for preventing sudden cardiac death (SCD) in arrhythmogenic right ventricular cardiomyopathy (ARVC). This study aims to identify cross-continental differences in utilization of primary prevention ICDs and survival free from sustained ventricular arrhythmia (VA) in ARVC.

Methods: This was a retrospective analysis of ARVC patients without prior VA enrolled in clinical registries from 11 countries throughout Europe and North America. Patients were classified according to whether they received treatment in North America or Europe and were further stratified by baseline predicted VA risk into low- (<10%/5 years), intermediate- (10%-25%/5 years), and high-risk (>25%/5 years) groups. Differences in ICD implantation and survival free from sustained VA events (including appropriate ICD therapy) were assessed.

Results: One thousand ninety-eight patients were followed for a median of 5.1 years; 554 (50.5%) received a primary prevention ICD, and 286 (26.0%) experienced a first VA event. After adjusting for baseline risk factors, North Americans were more than three times as likely to receive ICDs {hazard ratio (HR) 3.1 [95% confidence interval (CI) 2.5, 3.8]} but had only mildly increased risk for incident sustained VA [HR 1.4 (95% CI 1.1, 1.8)]. North Americans without ICDs were at higher risk for incident sustained VA [HR 2.1 (95% CI 1.3, 3.4)] than Europeans.

Conclusions: North American ARVC patients were substantially more likely than Europeans to receive primary prevention ICDs across all arrhythmic risk strata. A lower rate of ICD implantation in Europe was not associated with a higher rate of VA events in those without ICDs.

Keywords: Arrhythmogenic right ventricular cardiomyopathy; Implantable cardioverter-defibrillator; Primary prevention; Sudden cardiac death; Ventricular arrhythmia.

Structured Graphical Abstract

In this multi-national cohort of arrhythmogenic right ventricular cardiomyopathy patients, North American patients were much more likely to receive implantable cardioverter-defibrillator (ICDs) than European patients across all risk strata. Differences in rates of sustained ventricular arrhythmia (VA) between North America and Europe were limited to patients identified as high-risk by baseline risk estimates.

Figure 1

Cumulative rates of (left) primary prevention ICD implantation, (middle) sustained VA-free survival, and (right) LTVA-free survival (defined as VT at >250 b.p.m. or aborted SCD) according to geographic cohort. Shaded areas present 95% confidence intervals. Statistical significance was assessed using log-rank testing.

Figure 2

Cumulative rates of (top row) primary prevention ICD implantation, (centre row) sustained VA-free survival, and (bottom row) LTVA-free survival (defined as VT at >250 b.p.m. or aborted SCD) in low-risk (left column; <10% 5-year VA risk), intermediate-risk (middle column; 10%–25% 5-year VA risk), and high-risk (right column; >25% 5-year VA risk) sub-groups according to geographic cohort. Shaded areas present 95% confidence intervals. Statistical significance was assessed using log-rank testing.

Figure 3

Cumulative survival free from sustained VA in protected (patients with primary prevention ICD) and unprotected (patients without primary prevention ICD) according to geographic cohort. For protected patients, time 0 is the time of ICD implantation. Shaded areas present 95% confidence intervals. Statistical significance was assessed using log-rank testing.

Figure 4

Cumulative rates of (left) primary prevention ICD implantation and (right) sustained VA-free survival according to sex. Shaded areas present 95% confidence intervals. Statistical significance was assessed using log-rank testing.