MYOCARDIAL VIABILITY IN PATIENTS WITH Q-WAVE MYOCARDIAL-INFARCTION AND NO RESIDUAL ISCHEMIA

Background. Coronary revascularization in patients with persistent angina after myocardial infarction reduces the incidence of recurrent angina pectoris and myocardial infarction and improves left ventricular function. The results of revascularization after a Q wave myocardial infarction when there is no residual ischemia may depend on myocardial viability. Methods and Results. To determine whether there was viable myocardium in the infarct area in the absence of clinical and scintigraphic evidence of myocardial ischemia, 15 asymptomatic patients with a Q wave myocardial infarction, no redistribution on stress Tl-201 test, and single-vessel disease (>70% stenosis) with persistent anterograde blood flow were randomized to percutaneous transluminal coronary artery angioplasty (PTCA) or conservative medical treatment. After 2 months of follow-up, mean coronary blood flow measured by Doppler catheter in the infarct-related artery was higher in the PTCA treatment group (33+/-6 ml/min, n =8) than in the conservative treatment group (16+/-4 ml/min, n =7; p <0.05 between groups). The Tl-201 pathological-to-normal ratios measured on postexercise images did not change in patients treated conservatively during the follow-up period (DELTA=+1.1+/-2.2%; NS from baseline) but increased significantly in patients treated by PTCA (DELTA=+8.5+/-2.3%; p<0.01 from baseline; p<0.05 between groups). Segmental wall motion improved on left ventricular angiography 2 months after PTCA (DELTA=+11.5+/-2.2%; p<0.001 from baseline) significantly more than in the conservative treatment group (DELTA=+4.1+/-1.4%; p<0.05 between both groups). improvements of Tl-201 ratios and segmental wall motion indexes correlated significantly (r=0.73, p=0.002). The mild improvement of global left ventricular ejection fraction measured in the PTCA treatment group did not differ significantly from changes in the conservative treatment group. Conclusions. Successful angioplasty of the stenotic infarct artery in patients with a Q wave myocardial infarction and no residual ischemia improved coronary flow, Tl-201 uptake in the infarct area, and regional wall motion. Therefore, myocardial viability may last several weeks, as long as residual blood flow persists in the infarct-related artery. Optimal assessment of viability by imaging techniques should identify patients who are most likely to benefit from revascularization.