ARVC: Clinical Course and Predictors of Arrhythmic Risk

Study Questions:

What is the clinical course of arrhythmogenic right ventricular cardiomyopathy (ARVC), occurrence of life-threatening arrhythmic events (LAEs), and cardiovascular mortality?

Methods:

Clinical outcomes were analyzed for 301 consecutive patients enrolled in the ARVC registry. LAEs were defined as sudden cardiac death, aborted cardiac arrest, syncopal ventricular tachycardia (VT), electrical storm, or cardiovascular mortality. Predictors of LAE were determined with Cox multivariable analysis. Treatment efficacy was assessed comparing LAE rates during matched time intervals.

Results:

A first LAE occurred in 1.5 per 100 person-years between birth and 20 years, in 4.0 per 100 person-years between 21 and 40 years, and in 2.4 per 100 person-years between 41 and 60 years. Cumulative probability of a first LAE at follow-up was 14% at 5 years, 23% at 10 years, and 30% at 15 years. Higher risk of LAE was predicted by atrial fibrillation (hazard ratio [HR], 4.38; p = 0.002), syncope (HR, 3.36; p < 0.001), strenuous exercise (HR, 2.98; p = 0.03), hemodynamically tolerated sustained monomorphic VT (HR, 2.19; p = 0.02), and male sex (HR, 2.49; p = 0.01). No difference was observed in the occurrence of LAE before and after treatment with amiodarone, beta-blockers, sotalol, or ablation.

Conclusions:

The authors found that the highest risk of LAEs occurs between 21 and 40 years of age. They also identified clinical predictors of lethal events at follow-up.

Perspective:

The highest risk of LAE occurs between the third and fourth decade of life and rarely before adolescence. Therefore, the authors believe that screening for ARVC around age 11 or 12 years is reasonable. Prior studies appear to have underestimated LAEs due to analysis of data based on clinical history rather than through prospective clinical observation. In this analysis, male sex, participation in strenuous exercise, history of atrial fibrillation, syncope, and hemodynamically tolerated VT all may be harbingers of adverse events. In the absence of more sophisticated risk stratification schemes, it seems reasonable to recommend implantable cardioverter-defibrillator implantation in the presence of one or more of these risk factors. Neither medical therapy nor ablation appear to reduce the risk of adverse events, although that does not necessarily mean that there is no impact on the natural history of ARVC.

Keywords: Arrhythmias, Cardiac, Arrhythmogenic Right Ventricular Dysplasia, Atrial Fibrillation, Catheter Ablation, Death, Sudden, Cardiac, Defibrillators, Implantable, Exercise, Heart Arrest, Heart Defects, Congenital, Heart Failure, Primary Prevention, Risk Factors, Syncope, Tachycardia, Ventricular, Treatment Outcome


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