EFFECTS OF ISCHEMIA AND REPERFUSION ON QT DISPERSION DURING CORONARY ANGIOPLASTY

The effects of ischemia and reperfusion on QT interval dispersion (QTD : QT(max)-QT(min) in the 12-lead ECG) were analyzed in 15 patients (12 males, 57 +/- 13 years) undergoing coronary angioplasty (PTCA). All p atients had single-vessel coronary artery disease (only one greater th an or equal to 85% stenosis in a major coronary artery) and normal lef t ventricular function. All were in sinus rhythm with normal atriovent ricular and intraventricular conduction on the surface EGG. No patient wets on therapy that could affect the QT interval. The ECG was record ed (all 12 leads simultaneously) at 50 mm/s speed before the first bal loon inflation, at the end of the first inflation during PTCA, and at 30'' and 60'' during reperfusion following the first inflation. In ord er to avoid ischemic preconditioning, only recordings of the first inf lation were used. In each tracing QT(max) and QT(min) were valuated. A ll values were rate corrected using a simple linear equation (QT linea r corrected = QT + 0.154 [1-RR]). QTD increased significantly during b oth ischemia and reperfusion. QT(max) was not changed by ischemia and was increased by reperfusion. QT(min) was reduced by ischemia and incr eased by reperfusion. These results indicate that both ischemia and re perfusion alter ventricular repolarization, inducing a less homogeneou s ventricular recovery pattern.