Abstract

The haemodynamic changes that follow a meal can mimic the response to a vasodilator drug. To avoid overestimating the beneficial effects of treatment in uncontrolled studies, measurements of haemodynamic function are usually performed with patients in the fasting postabsorptive state. But such recordings are not representative of the resting patient during daily life. In this double blind placebo controlled study the short term haemodynamic effects of enalapril were assessed during 12 hours in 19 patients with moderate heart failure caused by dilated cardiomyopathy. The patients ate lunch and dinner and were studied in the absorptive and postabsorptive phases. In the placebo group systemic vascular resistance, mean arterial pressure, and the rate-pressure product fell significantly (5-16%) after lunch. Four hours after lunch the haemodynamic function had returned to baseline--that is the postabsorptive state. Enalapril, accentuated the haemodynamic effects during the absorptive state producing a larger post-prandial fall in mean arterial blood pressure and rate-pressure product and changes in the absorptive phase were maintained into the post-absorptive phase. Pulmonary wedge pressure fell significantly after treatment with enalapril. These overall changes during the study period indicated that enalapril reduced the preload and afterload on the heart--over and above the reduction produced by eating. These findings suggest that the effects of enalapril given at rest to patients with moderate heart failure unload the heart and enhance the reduction of afterload induced by meals.