Postprandial increase of cardiac output in patients with acute myocardial infarction

The influence on the hemodynamics of oral and intravenous nourishment containing the same amount of calories in comparison to isotonic solution of sodium chloride was studied in 14 patients with acute myocardial infarction. Forty minutes after administration of nourishment, a 34% increase in cardiac index, rising from 2.61 +/- 0.43 to 3.49 +/- 0.68 l/min/m2 was measured in the oral group, P less than 0.001. The increase was 22% (from 2.75 +/- 0.54 to 3.36 +/- 0.83 l/min/m2) in the intravenous group, P less than 0.025. Stroke index rose by 26% (from 33.4 +/- 7.8 to 42.1 +/- 10.6 ml/m2) in the oral group, P less than 0.025; and by 13% (from 32.7 +/- 8.3 to 37.0 +/- 9.7 ml/m2) in the intravenous group, P less than 0.05. No increases were seen in heart rate, mean blood pressure and pulmonary arterial diastolic pressure. The systemic vascular resistance decreased significantly in both groups. Thus, changes that mimic those seen during treatment with positive inotropic or vasodilating drugs were found. These effects have to be taken into account when assessing hemodynamic changes following cardiovascular medication.