We hypothesized that the chronic patency of culplit lesions after coronary angioplasty (PTCA) could be affected by myocardial viability of the target region. To assess the influences of myocardial viability on post-PTCA restenosis, a total of 50 patients (pts) with healed myocardial infarction and angina underwent resting state Thallium 2 0 1 (TI) scintigraphy just prior to PTCA, and follow-up coronary angiography 6 months after PTCA. Pts who needed intracoronary stenting were excluded. From the results of myocardial Tl uptake, pts were divided into 2 groups; Group 1 consisted of 25 pts (29 lesions) with fixed Tl defect; and Group2 consisted of 25 pts (28 lesions) with normal Tl uptake. In pts with normal Tl uptake, PTCA reduced restenosis compared to PTCA in pts with fixed Tl defect. Details were as follows; Conclusions: Myocardial viability which was confirmed by Tl scintigraphy itself appears to provide favorable chronic coronary patency after PTCA procedure.