Left ventricular hypertrophy in elderly hypertensive patients: a report from the European Working Party on High Blood Pressure in the Elderly trial. In a double-blind, placebo-controlled trial, 840 elderly hypertensive patients were randomly assigned to treatment with a combination of hydrochlorothiazide and triamterene or placebo; methyldopa or matching placebo was added to the treatment regimen if blood pressures remained high. After adjustment for age, gender, and body mass index, initial electrocardiographic (ECG) voltage measures of RaVL and SV1 + RV5 were significantly related to systolic blood pressure; RaVL was also related to diastolic blood pressure. After one year of treatment, the decrease in RaVL and SV1 + RV5 in the treated patients, adjusted for age and body mass index, were not correlated with the changes in systolic blood pressure, but the decreases in SV1 + RV5 were positively related to the decrease in diastolic blood pressure. After four years of treatment, the decreases in RaVL and SV1 + RV5 were significantly and positively related to the decrease in systolic blood pressure after adjustment for age and changes in body mass index. In a four-year cohort of 222 patients, most of the decreases in ECG voltages in the treated patients and the increases in the placebo patients were found to have occurred during the first year of treatment. The type of treatment (diuretics alone or diuretics plus methyldopa) did not affect ECG voltages during the first year of follow-up. Total and cardiovascular mortality were related to initial amplitude of RaVL, but the significant correlation disappeared after adjustment for age. 