Ethnic differences in electrocardiographic amplitude measurements

BACKGROUND: There is controversy regarding ethnic differences in electrocardiographic (ECG) patterns because of potentially confounding socioeconomic, nutritional, environmental and occupational factors. METHODS: We reviewed the first 1000 medical files of a multi-ethnic community, where all individuals shared similar living conditions. Only healthy adults age 15 to 60 years were included. Wave amplitudes were measured manually from the standard 12 lead ECG. Minnesota coding was used. RESULTS: ECGs from 597 subjects were included in the study: 350 Saudi Arabians, 95 Indians, 39 Jordanians, 17 Sri-Lankans, 39 Filipinos, and 57 Caucasians; 349 were men. The mean+/-SD of Sokolow-Lyon voltage (SLV) in men was significantly different among ethnic groups (2.9+/-0.86, 2.64+/-0.79, 2.73+/-0.72, 3.23+/-0.61, 2.94+/-0.6, 2.58+/-0.79 mV; P=0.0006, for Saudis, Indians, Jordanians, Filipinos, Sri-Lankans, and Caucasians, respectively). SLV was similar among ethnic groups in women. The prevalence of early transition patterns was also different among ethnic groups in men but not women (15.8%, 34.6%, 17.9%, 21.7%, 35.3%, 26.8% in Saudi, Indian, Jordanian, Filipino, Sri-Lankan, and Caucasian men, respectively, P=0.037). T wave amplitude was significantly different among ethnic groups in selected leads. CONCLUSIONS: ECG wave amplitude differs with ethnic origin even when other factors are similar. Using SLV of 3.5 mV as a criterion may overestimate the incidence of left ventricular hypertrophy in some ethnic groups. The pattern of high R wave in lead V1 is common in healthy adults in certain ethnic groups. T wave height differs with ethnic origin and sex.