Abstract 647: Important Role of Positive Family History of Sudden Death in Risk Stratification and Prevention of Death with the Implantable Defibrillator in Patients with Hypertrophic Cardiomyopathy

Abstract

Background: Prophylactic implantation of a cardioverter defibrillator (ICD) is indicated in the presence of risk factors (RF) for sudden death (SD) in patients with hypertrophic cardiomyopathy (HCM). Recent data show that even the presence of one RF warrants consideration of ICD placement. One such RF, a positive family history of SD involving close relatives, has important management considerations. However, there is a paucity of data on the long-term outcome of patients who received an ICD solely because of a family history of SD due to HCM.

Methods: We examined the rates of ICD-aborted SD in a cohort of 179 consecutive patients with HCM (113 males, mean age 45.2 ± 14 years) evaluated at two tertiary referral centers who received an ICD for the primary prevention of SD based on traditional RFs.

Results: Forty-two patients (23%) had a positive family history of SD in one or more first-degree relatives as their only RF for SD. Of the remaining 137 patients, 47 patients had a single RF (other than family history) and 90 patients were implanted because of the presence of ≥ 2 RFs. Over a mean follow-up of 4.6 ± 2.9 years, while the proportion of patients receiving appropriate ICD therapy varied, the differences were not statistically different among these subgroups (9.5% vs. 8.5% vs. 17.8% respectively; p = 0.2). Overall, patients with a single RF experienced appropriate ICD therapies at a rate of 2%/year compared with 4%/year for those with multiple RFs, however, there was no difference in 5-year survival free of SD for the three aforementioned subgroups (95% vs. 92% vs 89%, p = 0.5).

Conclusions: Patients with HCM who receive an ICD as primary prevention solely due to a family history of SD in a first-degree relative, experienced rates of appropriate ICD discharge which were comparable to those observed in patients who received an ICD based on other risk markers. Therefore, family history of SD is an important risk stratification marker in HCM, even when it is the sole evidence of risk.