Increase of cardiac output by afterload reduction in patients with severe congestive heart failure using nitroglycerin discs. A double-blind placebo-controlled haemodynamic study.

Abstract

In a double-blind crossover study, the haemodynamic effects of nitroglycerin discs were compared with placebo in 9 patients with severe chronic congestive heart failure. Hourly measurements were made throughout 24 hours for the placebo and the active treatment; the first 6 hours were used as a dose titration phase to achieve at least a 5 mmHg decrease in pulmonary arterial diastolic pressure. Active treatment, requiring 30 mg of nitroglycerin in most patients, produced a significant improvement in the cardiac index compared with placebo, as assessed from the end of the dose titration period to the 24th hour. Values determined as baseline, as the average from hour 7 to 24, and at the 24th hour for active discs were 2.3, 2.5 and 2.6 litres/min/m2, whereas for the placebo they were 2.3, 2.2. and 2.2 l/min/m2, respectively. Heart rate remained unchanged during the study, though mean systemic arterial blood pressure and vascular resistance were lower during active treatment. Right atrial and pulmonary arterial pressures did not change. In conclusion, nitroglycerin discs decrease afterload and improve cardiac performance over 24 hours in patients with heart failure.