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

Abstract

A normal coronary arterial tree has never been demonstrated by angiography at the time of acute myocardial infarction (AMI); among reported patients with myocardial infarction and angiographically normal coronary arteries, the angiograms were performed after healing, rather than during the AMI. Six explanations for the angiographically normal coronary arteries are considered: AMI never occurred; too large a myocardial mass or too little Hb or too low a perfusion pressure (shock) was present to supply the myocardium by a normal coronary tree; the coronary arteriograms were misinterpreted; coronary spasm caused the AMI; AMI was caused by a condition affecting only the intramural (intramyocardial) coronary arteries without involvement of the extramural coronary arteries; and AMI was caused by an occluding embolus which subsequently lysed or recanalized. Although each of these explanations 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.