Acute myocardial infarction and angiographically normal coronary arteries. An unproven combination

A number of necropsy studies have shown that among patients with fatal ischemic heart disease (IHD) at least one and usually two of the three major coronary arteries are greater than 75% narrowed by old atherosclerotic plaque. The introduction of selective coronary angiography allowed visualization of these vessels during life, and this technique demonstrated usually as severe coronary narrowing among patients with symptomatic IHD as necropsy has shown among patients with fatal IHD. Coronary angiography among patients with IHD manifested by acute myocardial infarction (AMI) has disclosed the following: when performed at the time of AMI, coronary angiography has always disclosed severe narrowing or complete obstruction of at least one of three major coronary arteries; when performed at the time of AMI, coronary angiography has never demonstrated a normal coronary tree; and when performed after healing of an AMI, coronary angiography has usually (> 99%) demonstrated severe narrowing of one or more of the three major coronary arteries, and rarely (< 1%), a normal coronary tree. The following statements are made concerning reported patients with 'myocardial infarction and angiographically normal coronary arteries.' An angiographically normal coronary tree has never been demonstrated at the time of AMI; among reported patients with 'myocardial infarction and angiographically normal coronary arteries,' the angiograms were performed after healing, rather than during the AMI; and, although there are several explanations for the occurrence of AMI and angiographically normal coronary arteries, and although each may be applicable on occasion, the most reasonable explanation appears to be acute coronary embolism with subsequent clot lysis, retraction, or recanalization, each of which may appear as 'angiographically normal.'