Coronary arteriographic findings during early hours of acute myocardial infarction: response to intracoronary injection of nitrates.

We performed coronary arteriography and gave intracoronary injection of nitrates within 8 hours after the onset of symptoms of acute myocardial infarction in eighteen patients. Improved distal filling or patency of the total occluded coronary artery after intracoronary injection of nitrates occurred in 4 of 18 patients. In one of four patients the first intracoronary nitrates injection failed to release the initial total occlusion, but after intracoronary Urokinase administration, the second nitrates injection succeeded to dilate the completely occluded coronary artery. Coronary arteriography was again performed in sixteen patients in the chronic stage (4-15 weeks after the onset of acute myocardial infarction) and ergonovine maleate was injected intravenously in seven patients. Focal spasm was induced by ergonovine injection in three patients in one of whom intracoronary nitrates failed to release the complete obstruction in the acute stage. We conclude that coronary spasm as well as intracoronary thrombosis plays an important role in the production of acute myocardial infarction.