The effect of ergonovine on coronary vasodilatory reserve in patients with angiographically normal coronary arteries.

Ergonovine produces physiologic coronary artery narrowing in many patients without focal coronary spasm. The effect of ergonovine-induced coronary vasoconstriction on coronary vasodilatory reserve is unknown. Therefore we studied 10 patients with atypical chest pain and angiographically normal coronary arteries. The heart rate and blood pressure were recorded continuously and coronary Doppler flow velocity was measured continuously with a 20 MHz Doppler-tipped catheter. Ergonovine caused diffuse narrowing of the vessels in all patients, with a 12% +/- 5% change in diameter of the left anterior descending coronary artery (p less than 0.001). There was a significant change in systolic (17% +/- 12% change; p less than 0.05) and mean arterial pressure (13% +/- 13% change; p less than 0.05), with no significant change in mean coronary flow velocity with ergonovine. Ergonovine also did not attenuate the maximal hyperemic response with papaverine. Thus despite an increase in myocardial demand and a decrease in caliber of conductance coronary vessels, the coronary autoregulatory flow responses were intact after the administration of ergonovine.