Haemodynamic effects of nifedipine (NIF) tablets were studied for 12 h in 10 patients with severe congestive heart failure due to ischaemic heart disease. A significant reduction (p < 0.001) in systemic and pulmonary vascular resistances and pulmonary capillary wedge pressure, was observed, at rest and after hand grip exercise, while cardiac index and stroke volume index increased significantly (p < 0.001). Reductions in systolic and diastolic blood pressure and increases in heart rate were hardly significant. Variations were found between 8 and 10 h (confidence interval). The maximum NIF plasma concentration was 33.3 ± 27.2 ng/ml after 6 h. The improvement in cardiac performance produced by NIF tablets was of substantial duration with twice-daily administration.