Coronary angiography during acute myocardial infarction: a search for spasm.

The mechanism of left anterior descending (LAD) obstruction was studied in 30 patients with transmural anterior myocardial infarction. Nitroglycerin was given by sublingual, intravenous, and intracoronary routes, and coronary angiography was performed in less than 6 hours. The ECG ST segment elevation fell more than 50% in two patients with sublingual nitroglycerin and in no patient with the addition of intravenous nitroglycerin. Intracoronary nitroglycerin restored slow LAD flow in one patient. Convex filling defects were seen in 17 patients compatible with intracoronary thrombus, and streptokinase was effective in 8 of 10. Studies suggest that the dominant coronary occlusive process early after the onset of injury is coronary thrombosis.