Implantable Cardioverter-defibrillator Therapy for Hypertrophic Cardiomyopathy: Usefulness in Primary and Secondary Prevention.

INTRODUCTION AND OBJECTIVES: Hypertrophic cardiomyopathy is a frequent cause of sudden death. Clinical practice guidelines indicate defibrillator implantation for primary prevention in patients with 1 or more risk factors and for secondary prevention in patients with a history of aborted sudden death or sustained ventricular arrhythmias. The aim of the present study was to analyze the follow-up of patients who received an implantable defibrillator following the current guidelines in nonreferral centers for this disease.

METHODS: This retrospective observational study included all patients who underwent defibrillator implantation between January 1996 and December 2012 in 3 centers in the province of Barcelona.

RESULTS: The study included 69 patients (mean age [standard deviation], 44.8 [17] years; 79.3% men), 48 in primary prevention and 21 in secondary prevention. The mean number of risk factors per patient was 1.8 in the primary prevention group and 0.5 in the secondary prevention group (P=.029). The median follow-up duration was 40.5 months. The appropriate therapy rate was 32.7/100 patient-years in secondary prevention and 1.7/100 patient-years in primary prevention (P<.001). Overall mortality was 10.1%. Implant-related complications were experienced by 8.7% of patients, and 13% had inappropriate defibrillator discharges.

CONCLUSIONS: In patients with a defibrillator for primary prevention, the appropriate therapy rate is extremely low, indicating the low predictive power of the current risk stratification criteria.