ELECTROCARDIOGRAPHIC FINDINGS IN A HEALTHY BIRACIAL POPULATION

It has been well documented that the prevalence of certain electrocard iographic (EGG) findings among individuals free of coronary heart dise ase (CHD) differs by race. However, it is not known whether these diff erences exist independently of CHD risk factors (e.g., hyper;tension). We examined the ECG tracings of 2,686 apparently healthy, middle-aged African-American and white men and women who participated in the Athe rosclerosis Risk in Communities Study and were at low risk of CHD. Usi ng the Minnesota Code, among men, 46% of African-Americans, but only 2 5% of whites, had a minor ECG finding (p <0.001). In women, 32% of Afr ican-Americans and 23% of whites had a minor ECG finding (p <0.01). Sp ecifically, the age-adjusted prevalences of high-amplitude R wave, ST elevation, T-wave findings, and prolonged P-R interval were statistica lly significantly higher in African-Americans. As for continuous ECG m easurements, the R wave in leads V-5 and V-6, the S wave in V-1, the J -point amplitude in leads V-2 and V-5, the P-R interval, and the Corne ll voltage (\S V-3\ + R aVL) for left ventricular hypertrophy were all significantly greater in African-Americans than in whites. However, i n both men and women, the heart rate corrected QT interval was shorter in African-Americans than in whites. All of these findings remained s tatistically significant after further adjustment for traditional CHD risk factors. These results suggest that racial differences in electro cardiograms may not be explained entirely by differences in establishe d CHD risk factors, and because current diagnostic ECG criteria are la rgely based on data from middle-aged white men and women, race should be considered in the interpretation of ECG findings. (C) 1998 by Excer pta Medica, Inc.