Black individuals have a higher proportion of increased electrocardiographic voltage and concentric left ventricular hypertrophy (LVH), as compared to white individuals. However, self-identified individuals in the United States have both African and European ancestry. In this probability-based cohort study with purposeful oversampling of self-identified black individuals in the Dallas County, Texas, investigators aimed to determine whether genetically determined African ancestry impacts the prevalence of increased electrocardiographic voltage or LVH. Participants (n=2077) underwent an electrocardiogram and cardiac magnetic resonance imaging (CMR). Both electrocardiographic voltage and markers of concentric LVH on CMR were assessed. After adjusting for several factors, including age, sex, and blood pressure, with both Black race and African ancestry entered in the same model, researchers found that African ancestry was associated with all CMR markers of LVH, including left ventricular concentricity (p=0.03), left ventricular wall thickness (p=0.03), prevalent LVH (p=0.04), and increased electrocardiographic voltage (p<0.001 for 12-lead voltage). However, in that same model, Black race was not associated with elevated electrocardiographic voltage (p=0.89 for 12-lead voltage), wall thickness (p=0.38), left ventricular concentricity (p=0.25), or prevalent LVH (p=0.55). Investigators therefore concluded that African ancestry was associated with increased electrocardiographic voltage and CMR markers of LVH, suggesting there is a genetic basis to the observed increased prevalence of these phenotypes in Black individuals.
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