Performance of Classic Electrocardiographic Criteria for Left Ventricular Hypertrophy in an African Population (original) (raw)

ECG criteria for left ventricular hypertrophy (LVH) have been almost exclusively elaborated and calibrated in white populations. Because several interethnic differences in ECG characteristics have been found, the applicability of these criteria to African individuals remains to be demonstrated. We therefore investigated the performance of classic ECG criteria for LVH detection in an African population. Digitized 12-lead ECG tracings were obtained from 334 African individuals randomly selected from the general population of the Republic of Seychelles (Indian Ocean). Left ventricular mass was calculated with M-mode echocardiography and indexed to body height. LVH was defined by taking the 95th percentile of body height-indexed LVM values in a reference subgroup. In the entire study sample, 16 men and 15 women (prevalence 9.3%) were finally declared to have LVH, of whom 9 were of the reference subgroup. Sensitivity, specificity, accuracy, and positive and negative predictive values for LVH were calculated for 9 classic ECG criteria, and receiver operating characteristic curves were computed. We also generated a new composite time-voltage criterion with stepwise multiple linear regression: weighted time-voltage criterionϭ(0.2366R aVL ϩ0.0551R V5 ϩ 0.0785S V3 ϩ 0.2993T V1)ϫQRS duration. The Sokolow-Lyon criterion reached the highest sensitivity (61%) and the R aVL voltage criterion reached the highest specificity (97%) when evaluated at their traditional partition value. However, at a fixed specificity of 95%, the sensitivity of these 10 criteria ranged from 16% to 32%. Best accuracy was obtained with the R aVL voltage criterion and the new composite time-voltage criterion (89% for both). Positive and negative predictive values varied considerably depending on the concomitant presence of 3 clinical risk factors for LVH (hypertension, age Ն50 years, overweight). Median positive and negative predictive values of the 10 ECG criteria were 15% and 95%, respectively, for subjects with none or 1 of these risk factors compared with 63% and 76% for subjects with all of them. In conclusion, the performance of classic ECG criteria for LVH detection was largely disparate and appeared to be lower in this population of East African origin than in white subjects. A newly generated composite time-voltage criterion might provide improved performance. The predictive value of ECG criteria for LVH was considerably enhanced with the integration of information on concomitant clinical risk factors for LVH. (Hypertension. 2000;36:54-61.) Key Words: left ventricle Ⅲ hypertrophy Ⅲ ethnic groups Ⅲ electrocardiography Ⅲ echocardiography L eft ventricular hypertrophy (LVH) is associated with a substantially increased risk of cardiac morbidity and mortality, 1-4 so its detection is of major importance, especially for individuals with hypertension or other cardiovascular risk factors. Although echocardiography has become the gold standard for LVH detection in clinical practice, ECG remains widely used due to its simplicity and accessibility. Caution should nevertheless be taken when using ECG criteria for LVH detection because they exhibit only limited accuracy (generally due to poor sensitivity). 5-8 Furthermore, their unrestricted applicability to nonwhite individuals remains to be demonstrated; historically, these criteria have been almost exclusively elaborated on and calibrated in white (or mixed) populations, and several interethnic differences in ECG characteristics have been demonstrated, especially in African individuals. 9-12 In the present study, we examined the performance of 9 classic ECG criteria for LVH prediction in a random sample of the African population of the Seychelles, with the use of echocardiography as the gold standard. Methods Study Population The present study was conducted in the Republic of Seychelles, which consists of 115 islets in the Indian Ocean, located 1800 km east of Kenya. The first inhabitants settled in Seychelles in the 1770s and were of French and African origin (from Madagascar and East Africa); they were later joined by small numbers of Chinese and