Ethnic differences in the identification of left ventricular hypertrophy in the hypertensive patient

Left ventricular hypertrophy (LVH) is more prevalent in black than white hy pertensives, but this difference is greater when identified by electrocardi ography (ECG) than by echocardiography. We evaluated the proposal that curr ent ECG criteria for LVH are less specific, and therefore, less useful, in blacks than whites. In a retrospective cross-sectional study, 408 subjects (271 white, 137 black) referred to a hypertension clinic for assessment of hypertension underwent measurement of blood pressure, ECG voltages (Sokolow -Lyon and Cornell sex-specific), and echocardiographic left ventricular mas s index (LVMI). Black subjects had greater ECG voltages than whites, even w hen closely matched for LVMI. In black subjects, current ECG criteria were twice as sensitive as in whites (Sokolow-Lyon: 44.9% v 22.5%, P = .003, Cor nell: 30.4% v 15.7%, P = .03). They were less specific in blacks using the Sokolow-Lyon criteria (73.5% v 86.8%, P = .02) but this failed to reach sig nificance using the Cornell criteria (83.8% v 91.8%, P = .07). When voltage criteria were adjusted to give matched sensitivities and specificities, re spectively, differences in specificity and sensitivity were no longer appar ent. Receiver operating characteristic curve analyses confirmed no signific ant differences in overall performance of either ECG criteria between black s and whites. In conclusion, ECG detection of LVH is insensitive in both et hnic groups. Sensitivity is higher in blacks due to higher LVMI in those wi th LVH. Apparent differences in specificity are due to ethnic differences i n ECG voltages that are unrelated to differences in LVMI. When these differ ences are taken into account, there are no overall differences in test accu racy. However, given the prognostic importance of the detection of LVH, cur rently accepted ECG voltage criteria for the detection of LVH remain of equ al or greater value in black hypertensives compared with whites. (C) 1999 A merican Journal of Hypertension, Ltd.