Race- and sex-specific ECG models for left ventricular mass in older populations. Factors influencing overestimation of left ventricular hypertrophy prevalence by ECG criteria in African-Americans

The validity of the reported high prevalence of left ventricular hypertrophy (LVH) among African-American men and women has been questioned owing to conflicting echocardiographic evidence. We used echocardiographic left ventricular mass (LVM) from M-mode measurements to evaluate associations between LVM, body size, and electrocardiographic (ECG) variables in 3,627 white and African-American men and women 65 years of age and older who were participants of the Cardiovascular Health Study (CHS), a multicenter cohort study of risk factors for coronary heart disease and stroke. ECG amplitudes used in LVH criteria were substantially higher in African-Americans, with apparent LVH prevalence 2 to 3 times higher in African American men and women than in white men and women, although there was no significant racial difference in echocardiographic LVM. The higher apparent LVH prevalence by Sokolow-Lyon criteria in African-American men is in part owing to smaller lateral chest diameter. In women, reasons for racial differences in ECG LVH prevalence remain largely unexplained although a small part of the excess LVH in African-American women by the Sokolow-Lyon criteria appears to be owing to a larger lateral chest semidiameter in white women. ECG variables alone were too inaccurate for LVM prediction, and it was necessary to incorporate in all ECG models body weight that was properly adjusted for race and sex. This resulted in modest LVM prediction accuracy, with R-square values ranging from .22 to.36. Race- and sex-specific ECG models introduced for LVM estimation with an appropriate adjustment for body size differences are expected to facilitate evaluation of LVH status in contrasting racial population groups.