Differential effects of antihypertensive agents on electrocardiographic voltage: results from the Appropriate Blood Pressure Control in Diabetes (ABCD) trial

Serial decline in electrocardiographic voltage in patients with increased left ventricular mass has been associated with a lower risk of cardiovascular events. We studied 468 patients with diabetes mellitus and hypertension in the Appropriate Blood Pressure Control in Diabetes (ABCD) trial. Patients were randomized in a stratified design to receive initial treatment with either enalapril or nisoldipine and to either intensive or moderate treatment goals. We measured an electrocardiographic index for increased left ventricular mass, the adjusted Cornell voltage, serially by treatment group. The association between changes in electrocardiographic voltage and cardiovascular events was defined with Cox proportional hazards analysis. In 5 years of follow-up, the decline in adjusted Cornell voltage was significantly greater for patients treated with enalapril than for patients treated with nisoldipine (repeated measures analysis of variance P = .002). In the Cox proportional hazards model, treatment assignment (enalapril vs nisoldipine) was the strongest predictor of cardiovascular events, but the presence of coronary disease at baseline, the duration of diabetes mellitus, and change in voltage were also independent predictors of cardiovascular events. In the ABCD study, enalapril treatment was associated with a lower risk of myocardial infarction. The reduction in left ventricular mass as reflected by diminished electrocardiographic voltage may explain some, but not all, of the effect of enalapril in this study.