Effects of eating on cardiac performance in congestive heart failure

We assessed the effects of ingestion of a meal on cardiac performance in patients with chronic severe congestive heart failure. A group of 32 patients underwent right heart catheterization on the day prior to study. Patients then fasted overnight (12 hours). In the morning, baseline hemodynamic measurements were obtained on all patients; then 11 patients (group 1) consumed a liquid meal of 317 kcal, and 21 patients (group 2) received a placebo medication and continued fasting. Hemodynamic measurements were then obtained at intervals over two hours. Significant changes were seen in group 1 only. Cardiac index increased 22 percent, stroke work index increased 14 percent, pulmonary arterial wedge pressure decreased 20 percent, and systemic vascular resistance decreased 22 percent in group 1. This study demonstrates an important effect of ingestion of a meal on cardiac performance in patients with heart failure. To avoid overestimating the beneficial effects of therapy, eating must be carefully controlled when assessing the effects of various therapies in these patients.