Effect of the vasodilator trimazosin versus placebo on exercise performance in chronic left ventricular failure.

The effect of the vasodilator trimazosin versus placebo on exercise duration until marked dyspnea was evaluated in a double blind randomized study in 16 patients with chronic left ventricular failure despite digitalis and diuretic therapy. Trimazosin caused a reduction in resting systolic and diastolic blood pressures and in resting product of systolic blood pressure times heart rate. The improvement in exercise duration from the average of values during the baseline and single blind placebo periods was greater after 3 and 6 weeks of trimazosin therapy (300 and 450 mg daily) after 3 and 6 weeks of double blind placebo therapy (P is less than 0.025). Four of eight patients receiving trimazosin had disappearance of pulmonary venous congestion on chest roentgenography compared with none of eight patients receiving placebo. These preliminary data suggest that trimazosin may be effective in treating chronic left ventricular failure.