Myocardial perfusion and left ventricular (LV) diastolic filling were studied in 67 patients with mild to moderate hypertension and left ventricular hypertrophy (LVH). The control group consisted of 28 subjects with no cardiac pathology. LV mass assessed by M-mode echocardiography was obtained in all patients. LV diastolic filling was estimated by pulsed Doppler echocardiography before and after intravenous administration of verapamil (0.145 mg/kg) and contrast ventricular angiography during intracoronary administration of verapamil (1 to 1.5 mg). Myocardial perfusion was estimated by technetium-99m scintigraphy with albumin microspheres and thallium-199 scintigraphy in combination with intravenous dipyridamole. Coronary artery disease was excluded in 42 patients by coronary angiography. Pulsed Doppler echocardiography demonstrated an inverse correlation between the LV mass index and the ratio of peak early to peak atrial velocity (r = -65, P less than .001). Twelve of 20 patients experienced transient "normalization" of LV diastolic filling during intravenous administration of verapamil. In addition, 6 of 22 patients with LVH had an increase in end-diastolic volume owing to enhanced segment relaxation of the injected artery during intracoronary administration of verapamil. Myocardial perfusion defects assessed by scintigraphy with albumin microspheres were observed in 8 of 13 patients but in no controls. According to 199T scintigraphy data, myocardial perfusion defects were more common in patients with LVH (P less than .05). Thus, essential hypertension combined with LVH appears to result in severe cardiac dysfunction, which is probably associated with changes in small vessel walls.