[Comparison of exercise-stress single photon emission computed tomography with thallium-201 reinjection and postextrasystolic potentiation to assess myocardial viability in patients with myocardial infarction]

Abstract

Myocardial viability was examined in 20 patients with myocardial infarction 24 +/- 3 (mean +/- standard deviation) days after onset. Postextrasystolic potentiation (PESP) was measured by left ventriculography and thallium-201 (Tl) single photon emission computed tomography (SPECT) redistribution was assessed after stress loading and reinjection of Tl. The results were compared with the improvement of left ventricular segmental wall motion after coronary revascularization which was performed successfully in all patients. The uptake of Tl was impaired initially in 41 segments, classified into three groups: normal group, 13 segments with smooth reversion to normal; new fill-in group, 15 segments with a new fill-in after reinjection of Tl; no fill-in group, 13 segments with no fill-in after reinjection. When evaluated by the PESP before coronary revascularization, segmental wall motion was significantly augmented in all segments in the normal group and new fill-in group (p < 0.001), but not in the no fill-in group. After coronary revascularization, left ventriculography revealed that segmental wall motion was significantly improved in normal group and new fill-in group, but not in the no fill-in group except for mild improvement in five segments. The sensitivity and specificity of PESP (90% and 93%) and Tl SPECT (80% and 100%) for improvement of segmental wall motion after the coronary revascularization were very high, with the accuracy of either method attaining 87%. This result indicates that both Tl SPECT and PESP are useful for detecting viable myocardium in patients with recent myocardial infarction.