Efficacy of antiarrhythmic drugs in arrhythmogenic right ventricular cardiomyopathy: a report from the North American ARVC Registry.

OBJECTIVES

This study sought to examine the efficacy of empiric antiarrhythmic drugs in a rigorously characterized cohort of arrhythmogenic right ventricular cardiomyopathy (ARVC) patients.

BACKGROUND

Antiarrhythmic drugs are important in protecting against ventricular arrhythmias in ARVC, but no studies have provided data in a group rigorously screened for the disease.

METHODS

Antiarrhythmic medicines were examined in all subjects with implantable cardioverter-defibrillators (ICDs) enrolled in the North American ARVC Registry. A Cox proportional hazards model was used to account for time on each drug, and a hierarchical analysis was performed for repeated measures within individuals.

RESULTS

Ninety-five patients were studied, with a mean follow-up of 480 +/- 389 days. Fifty-eight (61%) received beta-blockers, and these medicines were not associated with an increased or decreased risk of ventricular arrhythmias. Sotalol was associated with a greater risk of any clinically relevant ventricular arrhythmia as defined by sustained ventricular tachycardia or ICD therapy (hazard ratio [HR]: 2.55, 95% confidence interval [CI]: 1.02 to 6.39, p = 0.045), but this was not statistically significant after adjusting for potential confounders. An increased risk of any ICD shock and first clinically relevant ventricular arrhythmia while on sotalol remained significant after multivariable adjustment. Those on amiodarone (n = 10) had a significantly lower risk of any clinically relevant ventricular arrhythmia (HR: 0.25, 95% CI: 0.07 to 0.95, p = 0.041), a finding that remained significant after multivariable adjustment.

CONCLUSIONS

In a cohort of well-characterized ARVC subjects, neither beta-blockers nor sotalol seemed to be protective. Evidence from a small number of patients suggests that amiodarone has superior efficacy in preventing ventricular arrhythmias.