The aim of this study was twofold: to evaluate the frequency of reversibility of segmental post-subendocardial infarction asynergy after coronary angioplasty, and to test the predictive value of the redistribution phenomenon during stress Thallium scintigraphy with respect to the reversibility of segmental asynergy. The inclusion criteria for this study were: previous postsubendocardial myocardial ischaemia with residual resting or effort ischaemia documented with or without the Thallium test, segmented asynergy documented by quantitative analysis of the ventriculography, complete correction of coronary angioplasty of stenotic single or double vessel disease, a balanced coronary distribution or dominant left coronary in cases of lesion of the circumflex artery. Out of 254 consecutive angioplasty procedures 39 patients met these inclusion criteria. The location of the subendocardial infarct (SEI) was anterior in 17 cases and inferior in 22 cases. The study protocol included a Thallium scintigraphy from the 10th day after SEI, ventriculography 24 hours later, angioplasty and control ventriculography 24 hours after angioplasty. Comparison of the two ventriculographies opposed Group A (reversible asynergy) and Group B (irreversible asynergy) according to criteria defined in 15 normal subjects whose average regional ejection fraction (REF) was 0.53 +/- 0.11. This result enables definition of normal segmental motion if the REF greater than 0.30 (mean--2 SD); hypokinetic if the REF greater than 0.30 or akinetic if the REF less than 0.10 (mean--4 SD). An increase of REF of 0.15 (50% of the minimal normal value) allowed definition of reversibility of asynergy. By these criteria, 19 patients (48.7%) had reversible asynergy after PTCA; 20 had definitive asynergy (51.3%).(ABSTRACT TRUNCATED AT 250 WORDS)