Rapid reduction of blood pressure by vasodilators in severe hypertensives has been associated with T-wave inversion. The significance of these changes in the absence of chest pain or other manifestations of ischemia is not known. To determine if these T-wave inversions are due to myocardial ischemia, we obtained electrocardiograms and left ventricular wall motion studies (2-D echocardiography) before and 1 h after rapid blood pressure reduction with nifedipine in 23 severe hypertensives. One hour after 10 mg nifedipine blood pressure was markedly reduced from 189 +/- 6/117 +/- 3 (mean +/- SE) to 151 +/- 5/91 +/- 3 mm Hg (P less than .001). New T-wave inversions developed in 6 of 23 (26%) subjects, but blinded evaluation of 2-D echocardiograms revealed no new wall motion abnormalities. Wall motion score, which at pretreatment was abnormal in 11 of 23 patients, improved significantly after nifedipine from 1.4 +/- 0.1 to 1.2 +/- 0.1 (P less than .05). Therefore, rapid and marked reduction of blood pressure with nifedipine is accompanied by a high incidence of asymptomatic T-wave inversions which are not accompanied by left ventricular wall motion abnormalities, suggesting that significant myocardial ischemia did not occur.