Blacks as Compared to Whites Do Not Have an Increased Prevalence of Reduced Left Ventricular Ejection Fraction in the General Population

Abstract

Objectives: To evaluate racial differences in the prevalence of left ventricular dysfunction in the general population. Background: Because of the higher prevalence of risk factors for heart failure in blacks, including hypertension, obesity, and LVH, we hypothesized that left ventricular dysfunction would also be more common in this ethnic group. Few data are presently available which address this question. Methods: In the Dallas Heart Study, a probability-based sample of Dallas County, we performed cardiac MRI on 1335 black and 858 white participants to measure LVEF and LV volumes. We compared the prevalence of reduced LVEF and distribution of left ventricular end-diastolic and end-systolic volumes (LVEDV and LVESV, respectively) in the two ethnic groups. Results: The prevalence of a reduced LVEF, whether defined as <50%, <55%, or <60%, did not differ between black vs. white women (p ≥ 0.7 for each) or men (p ≥ 0.4 for each), despite previously demonstrated significant differences in the prevalence of hypertension and LVH in these groups. The prevalence of low EF in blacks vs. whites was also not significant when using a recently-defined gender-specific threshold for low LVEF (5.4% vs. 3.2%, respectively; p = 0.1). In subgroup analysis, there were no ethnic differences in prevalent reduced LVEF in participants with hypertension (p > 0.2), obesity (p > 0.2), or age greater than 45 years old (p > 0.3) for each LVEF cut-off. Mean LVEDV and LVESV indexed to body surface area (BSA) were also comparable in the two ethnic groups. The mean LVEDV/BSA for black and white men were 55.3 and 54.2 ml/m2, respectively (p = 0.3), and for black and white women were 49.0 and 50.4 ml/m2, respectively (p = 0.1). The mean LVESV/BSA for black and white men were 16.7 and 17.2 ml/m2, respectively (p = 0.4), and for black and white women were 13.3 and 13.0 ml/m2, respectively (p = 0.7). Conclusions: Despite having a higher prevalence of risk factors for heart failure, blacks as compared to whites surprisingly did not have a higher prevalence of reduced LVEF or evidence of ventricular enlargement in the general population.