抄録
We examined the effectiveness of QT interval behavior in evaluating the viability of reperfused infarct-related myocardium in patients with myocardial infarction. Exercise thallium-201 single photon emission computed tomography was performed six months following successful direct angioplasty on 67 patients (60.6 ± 11.5 years) with myocardial infarction. QTc interval and QT dispersion from 12 lead electrocardiography and the number of perfusion defect areas from SPECT images were measured at rest and during exercise. Sixty-two patients with a resting perfusion defect were divided into 3 groups based on the SPECT image patterns. Group A consisted of 11 patients with partial redistribution, Group B consisted of 18 patients with reverse redistribution, and Group C consisted of 32 patients with fixed defect. The change in the number of defect areas from rest to exercise was related to the change in maximal QTc interval (y =15.4-3.31X, r = 0.298, p = 0.0138) . The maximal QTc interval was longer in all groups with myocardial infarction compared with 12 normal volunteers at rest (p<0.05), and increased during exercise in group B (465.8 ± 46.6 to 487.8 ± 27.2, p = 0.0193) and group C (458.7±25.4 to 479.5±31.1, p<0.0001), but not in group A (458.9± 26.4 to 462.1 ± 25.8, p = not significance) . QT dispersion decreased during exercise in the former 2 groups (62.9 ± 30.3 to 42.3 ± 14.7, in group B, p = 0.0 102, 53.8 ±20.3 to 41.7± 18.7, in group C, p=0.0002), but not group A (45.6±22.3 to 32.8±9, in the group A, p = no significance) . QT interval behavior is an effective predictor of scarred myocardial viability following reperfusion.
