Exercise-induced negative U waves in precordial leads as a marker of viable myocardium in patients with recent anterior myocardial infarction

Patients with recent anterior myocardial infarction and a significant steno sis in the left anterior descending coronary artery were divided into two g roups according to the presence (Group A, n=24) or absence (Group B, n=77) of negative U waves in the precordial leads during exercise stress test to compare the coronary arteriographic findings. Both total occlusion of the l eft anterior descending coronary artery (79% vs. 31%, P<0.01)) and good (in dex=2,3) collateral circulation to the territory of this artery (92% vs. 36 %, P<0.01) were observed more often in group A than in group B. In order to determine whether detection of exercise-induced negative U waves in precor dial leads can predict the presence of viable myocardium, the 56 patients ( 20 of group A and 36 of group B) with total or subtotal occlusion of the le ft anterior descending coronary artery were studied further. The coronary a rteriographic and exercise Tl-201 scintigraphic findings were compared betw een the groups. Good collateral circulation to the territory of this artery was observed significantly (P<0.05) more often in group A (100%) than in g roup B (61%). Patients with multivessel disease were significantly (P<0.05) more prevalent in group A (70%) than in group B (33%). The incidence of a significant partial redistribution in the anteroseptal area in the Tl-201 i mages 4 h after exercise was significantly (P<0.01) higher in group A (85%) than in group B (39%). In 29 patients with anterior Q-wave myocardial infa rction and exercise-induced ST elevation in precordial leads, a significant Tl-201 redistribution in the anteroseptal area was observed in 8 (80%) of 10 patients of group A in contrast to only 4 (21%, P<0.05) of 19 in group B . In the diagnosis of the viability associated with Tl-201 redistribution i n the anteroseptal area by the finding of exercise-induced negative U waves , the sensitivity was 67% and the specificity was 88% in these patients. We conclude that exercise-induced negative U waves in precordial leads are a convenient and specific marker for the presence of viable myocardium in pat ients with recent anterior myocardial infarction. (C) 2000 Elsevier Science Ireland Ltd, All rights reserved.