Abstract 3355: Relationship of Race to Risk Stratification for Sudden Cardiac Death in Patients With Hypertrophic Cardiomyopathy
Purpose: Autopsy data from the US demonstrate that the prevalence of HCM-related deaths is greater in young athletes of African descent compared to their Caucasian counterparts suggesting that HCM may exhibit a more malignant course in Black individuals. The aim of the study was to compare the prevalence of established risk factors for SCD in a cohort of African/Afro-Caribbean (Black patients; BP) and Caucasian patients (CP) with HCM.
Methods: Between 2001 and 2009, 74 patients with a diagnosis of HCM (24 BP) were assessed and underwent annual risk stratification testing for conventional risk factors including:
Severe (≥30 mm) left ventricular hypertrophy,
Family history of premature sudden death,
Abnormal blood pressure response to exercise and
Non-sustained ventricular tachycardia (NSVT) on Holter monitor or during exercise.
Results: Both groups were similar with respect to age (BP vs. CP; 43.8±15.5 vs. 49.6±14.4 years, p=0.12), gender (BP vs. CP; 54% vs. 60% male gender, p=0.80) and left ventricular wall thickness (BP vs. CP; 17.04±3.70 vs. 19.00±4.16 mm, p=0.054). None of the patients exhibited a ventricular wall thickness ≥30 mm. There was no significant difference between BP and CP with HCM in relation to the prevalence of syncope (12.5% vs. 16%, p=0.49), family history of SCD (21% vs. 12%, p=0.91) or abnormal exercise blood pressure response (21% vs. 22%, p=0.58). In contrast, NSVT was identified more frequently in CP compared to BP (36% vs. 12.5%, p=0.03). Similar proportions of Black and Caucasian patients exhibited ≥2 risk factors to indicate an increased risk of SCD (12.5% vs. 18%, p=0.23).
Conclusion: HCM patients of African/Afro-Caribbean origin do not exhibit an increased frequency of established risk factors for SCD compared to Caucasian subjects to indicate a more malignant course of the disease in this particular ethnic group. On the contrary, CP had an increased frequency of NSVT possibly indicating an increased risk of SCD. Although it is conceivable that exercise on a background of HCM may have a more pronounced effect in Black individuals, it is more likely that the increased death rates from HCM observed in Black athletes in the US reflects higher participation rates, in common sporting disciplines.