Acute coronary syndromes: No-reflow--an ominous sign of cardiac dysfunction.

Mechanical reperfusion in acute myocardial infarction does not always result in desirable optimal microvascular perfusion. Failure to achieve a normal myocardial blush in the infarcted region by contrast injection immediately after percutaneous coronary intervention--the 'no-reflow' phenomenon--is an ominous sign whose prognostic importance may go beyond its intimate association with infarct size.