Role of family history of sudden death in risk stratification and prevention of sudden death with implantable defibrillators in hypertrophic cardiomyopathy

The selection of patients with hypertrophic cardiomyopathy (HC) for the primary prevention of sudden death (SD) with implantable cardioverter- defibrillators (ICDs) has been determined by the assessment of 5 risk factors. We examined one of these markers, the family history of HC-related SD in first-degree relatives, for which few data are available. The rate of appropriate ICD interventions was assessed in 177 consecutive patients with HC (63% men, age 45 ± 14 years) who had undergone prophylactic implantation at 2 tertiary centers, according to the identification of ≥1 risk markers. During a follow-up period of 4.6 ± 3 years, 25 patients (14%) had experienced appropriate ICD interventions for ventricular tachycardia/ fibrillation. The patients with a risk profile that included a family history of SD experienced interventions at a similar rate (3.7/100 person-years) as the patients without a family history of SD (3.1/100 person-years, p = 0.2). The rate and frequency of appropriate ICD interventions in 42 patients who had undergone implantation solely because of a family history of SD was 2.2/100 person-years (4/42, 10%), similar to that for patients with one risk factor other than SD family history (3.4%/100 person-years; 7/50, 14%; p = 0.2) and patients with multiple risk factors with (4.5/100 person-years; 9/49, 18%) and without (3.5/100 person-years; 5/36, 14%) a family history of SD (p = 0.8). In conclusion, a family history of SD is an important risk marker in patients with HC. Patients receiving ICDs for primary prevention because of a family history of HC-related SD, whether as an isolated risk factor or combined with other markers, experienced rates of appropriate ICD discharge comparable to that of other patient subsets with increased risk.