Clinical and haemodynamic effects of low dose captopril in severe chronic heart failure.

1 The clinical and haemodynamic effects of low doses of the oral converting-enzyme inhibitor captopril were studied in 18 patients with severe chronic heart failure. Increasing doses of 1 mg, 2.5 mg, 6.25 mg, 12.5 mg, and 25 mg captopril were given at two hour intervals with haemodynamic monitoring. Graded haemodynamic improvement (increased stroke volume index and reduced mean pulmonary capillary wedge pressure) occurred from one hour with reduction of blood pressure closely associated. 2 Maximal haemodynamic improvement for the group was seen at six and seven hours after the 6.25 mg and 12.5 mg doses, when stroke volume index was increased by 35% and mean pulmonary capillary wedge pressure reduced by 40% from control. Captopril 12.5 mg-50 mg eight hourly was continued long-term but withdrawn in two patients with symptomatic hypotension and one patient with altered taste. 3 Four patients died and one was non-compliant with therapy. At three months 10 patients showed significant improvement in symptoms, treadmill exercise duration, and echocardiographic indices of left ventricular size and function. The results of repeat haemodynamic measurements were similar to optimal measurements obtained during the initial study. 4 At two years six patients remained alive, five having maintained their symptomatic improvement. Thus small doses of captopril produce haemodynamic improvement in heart failure with a closely associated reduction of blood pressure. Symptomatic and haemodynamic benefit is maintained with long-term treatment.