[Myocardial infarction with normal coronary arteries: a condition with multiple etiology and variable prognosis]

Myocardial infarction with angiographically normal coronary arteries was recognized more than 30 years ago. Since then, various series of patients with such condition have been described, but the etiology and pathogenesis still remain a matter of debate. Evidence exists for a role of coronary vasospasm, thrombosis, embolization and inflammation, per se or combined, in determining the occurrence of myocardial infarction with angiographically normal coronary arteries. Endothelial dysfunction, possibly superimposed to non-angiographically evident atherosclerosis, may be an underlying common feature predisposing to the acute event. Additionally, myocarditis may explain some of these occurrences. Myocardial infarction with normal coronary arteries is therefore likely to be the result of multiple pathogenetic mechanisms. Although most reports emphasize the good prognosis of this condition, in general much better than myocardial infarction with coronary artery disease, prognosis is likely variable according to the underlying mechanism. This review summarizes current knowledge on this condition and examines areas of recent progress.