Abstract 2399: African-Americans with Congestive Heart Failure Have More Arrhythmias than Caucasians Independent of the SCN5A S1103Y Genotype
Background: Racial differences are playing a growing role in the medical management of heart failure (HF). Race can also affect arrhythmia susceptibility, as shown by the identification of the S1103Y SCN5A Na-channel polymorphism in African-Americans (AAs) with arrhythmias. Sudden cardiac death and the impact of this SCN5A polymorphism in AAs with heart failure are not well studied.
Methods: We examined demographic data, ECGs, echocardiograms, S1103Y genotypes and clinical outcomes (death, appropriate ICD shocks for VT/VF) in heart failure subjects (EF < < 26 > 30%, ICDs) enrolled in the multicenter Genetic Risk Assessment of Defibrillator Events (GRADE) study.
Results: We studied 951 subjects (87% Caucasian, 13% AA; 71% ischemic; mean f/u 24 ± 16 months; NYHA Class 2.2 ± 0.6; EF 21 ± 6%). Compared to Caucasians, AAs had slightly worse cardiac function (EF 19 ± 7 vs. 21 ± 6; p < 0.001), were more likely to be nonischemic (50% vs. 25%; p < 0.001), and had similar QTc intervals (468 ± 56 vs. 472 ± 54 ms; p < 0.41). AAs had more appropriate ICD discharges (1-yr 18 vs. 9%, 2-yr 40 vs. 15%; p < 0.001) but no difference in mortality (1-yr 6 vs. 8%, 2-yr 22% vs. 13%; p = 0.12; Figure⇓). In AAs, there was no significant difference in appropriate ICD discharges by SS1103 (n = 79) vs. SY+YY1103 (n = 18) SCN5A genotype (1-yr 16 vs. 17%, 2-yr 45 vs. 17%; p = 0.32), although there was a trend towards higher mortality for Y allele carriers (1-yr 3 vs. 16%, 2-yr 17 vs. 28%; p = 0.08) and no QTc interval differences.
Conclusions: African-Americans with heart failure had more arrhythmic episodes compared to Caucasians, and this is not explained by SCN5A S1103Y genotype. These data support increased use of ICDs in AA with heart failure.