In 12 patients with significant coronary artery disease (CAD) segmental and global left ventricular (LV) function was studied by quantitative cineventriculography before and 5 min after sublingual administration of 20 mg nifedipine (N). Significant increase of mean relative hemiaxes shortening of inferior (24 +/- 10%----38 +/- 13%) and apical (31 +/- 10%----42 +/- 14%) wall segments, as well as improvement of ejection fraction (61 +/- 14%----75 +/- 14%), mean circumferential fiber shortening velocity (1.05 +/- 0.46 ccf/s----1.41 +/- 0.47 ccf/s) and end-systolic volume (57 +/- 26 ml----37 +/- 27 ml) of the LV were found after administration of N. The highest increase of segmental contraction (28 +/- 11%----44 +/- 16%; p less than 0.001) was noted in 20 noninfarcted wall segments, perfused by significantly stenosed coronary arteries. No significant improvement could be detected in 6 infarcted segments. A second group consisting of 12 patients with CAD showed a significant reduction of the aortic end-diastolic pressure (89 +/- 9 mm Hg----79 +/- 7 mm Hg; p less than 0.001) but no significant change of isovolumic contractility indices and heart rate was observed after N administration. The study suggests that acute improvement of LV function, found 5 min after sublingual administration of N, is mainly due to improved contraction of ischemic myocardial wall segments. Among different possible reasons for this improvement LV afterload reduction after N administration seems to be the most important one.