Coronary hemodynamic effects of ergonovine maleate in human subjects

The coronary hemodynamic effects of ergonovine maleate were examined in 15 patients with a chest pain syndrome not thought to be variant angina. Ergonovine was given intravenously in sequential doses of 0.05, 0.1 and 0.25 mg while measurements were made of systemic hemodynamic variables, coronary sinus blood flow and coronary arteriovenous oxygen difference at intervals during the protocol. Coronary arterial diameters were measured from the 35 mm cineangiogram. Despite an increase in myocardial metabolic demand, as estimated with the heart-rate-blood pressure product, there was no apparent increase in coronary vascular resistance. In addition, there was a significant widening of the coronary arteriovenous oxygen difference in five of the seven patients in whom it could be measured. However, neither chest pain nor ischemic electrocardiographic changes were evoked. Although ergonovine also produced a diminution in epicardial coronary arterial diameters, this effect was not sufficient to explain the absence of appropriate coronary vasodilation. These results suggest that ergonovine may limit the normal vasodilatory response of the arteriolar bed to increases in myocardial metabolic demand.