Usefulness of QRS voltage correction by body mass index to improve electrocardiographic detection of left ventricular hypertrophy in patients with systemic hypertension.

Obesity reduces the accuracy of voltage-based electrocardiographic (ECG) criteria for diagnosis of left ventricular (LV) hypertrophy. We developed a new ECG score for diagnosis of LV hypertrophy, defined either by a typical strain pattern or a product of the Cornell voltage (R wave height in lead aVL plus S wave depth in lead V3) by body mass index >604 mm∙kg/m(2). We examined a population of 2,747 untreated hypertensive subjects (mean age 49 ± 11 years) with good quality ECG and echocardiographic tracings. Several traditional ECG criteria for LV hypertrophy were compared with the new score, with echocardiographic LV mass taken as reference. Among the tested criteria, the highest sensitivity combined with specificity was yielded by the new score (sensitivity 36.1%, 95% confidence interval [CI] 32.9 to 39.4; specificity 90.5%, 95% CI 89.1 to 91.8; and accuracy 73.1%, 95% CI 71.5 to 74.8). Prevalence of ECG LV hypertrophy with the new score was 18%. On the basis of comparisons between areas under the receiver operating characteristic curves, the best performance was achieved by the new score with respect to other ECG criteria for LV hypertrophy (all p <0.0001). In conclusion, correction of Cornell voltage by body mass index as a marker of obesity improves the performance of traditional electrocardiography for diagnosis of LV hypertrophy in patients with hypertension.