In 26 previously untreated patients with essential hypertension (mean age 49.7 +/- 11 years), the effect of long-term treatment with the calcium antagonist gallopamil (n = 13, 100 mg; n = 13, 150 mg daily) on blood pressure and left ventricular hypertrophy (LVH) was studied. After the treatment of 22.3 +/- 2.5 months, the blood pressure of 157 +/- 19/103 +/- 84 mm Hg at rest prior to therapy was significantly (p less than 0.001) reduced to 130 +/- 12/82 +/- 7.3 mm Hg. Blood pressure reduction was accompanied by a significant (p less than 0.001) decrease in left ventricular mass index from 170 +/- 49.8/m2 to 150 +/- 44 (11.9%) and 116 +/- 26 (31.9%) after 8.2 and 22.3 months, respectively. Interventricular septum (14.2 to 13.2 and 11.8 mm; 16.9%) and posterior wall thickness (11.5 to 10.4 and 9.4 mm; 18.3%) were also significantly (p less than 0.001) reduced, whereas left ventricular dimensions and fractional shortening were unchanged. We conclude that LVH from hypertension can be lessened by calcium antagonists without deterioration of left ventricular function.