DOES INCREASED QT DISPERSION IN THE ACUTE-PHASE OF ANTERIOR MYOCARDIAL-INFARCTION PREDICT RECOVERY OF LEFT-VENTRICULAR WALL-MOTION

QT dispersion has been recognized as an undesirable marker because of its association with arrhythmogenicity in patients with myocardial inf arction, but the relation between QT interval dispersion and wall moti on abnormalities has not been clarified. After the introduction of rep erfusion therapy, it was recognized that T waves were inverted twice i n the course of myocardial infarction. An investigation was made of th e clinical significance of QT dispersion in relation to the presence o f inverted T waves and left ventricular wall motion abnormalities in 3 4 patients mean age, 59 years) with acute anterior myocardial infarcti on who underwent successful reperfusion therapy. The amplitude of the deepest inverted T waves occurring within the first 3 days (T-1) and a fter 3 days (T-2) Of myocardial infarction were measured in electrocar diographic (ECG) lead V-3. On the ECGs on which T-1 and T-2 were recor ded, QT dispersion was calculated (QTd(1), QTd(2)), and T-1 and T-2 we re correlated with QTd(1) (r = .65) and QTd(2) (r = .47), respectively . The difference between the extent of asynergy in the acute phase and the chronic phase, which was evaluated by the centerline method, was correlated with T-1 (r = .63) and QTd(1) (r = .67). Patients with a QT d(1) of 0.1 second or longer showed a greater change in the extent of asynergy (23.4 +/- 13.1% vs 4.9 +/- 9.8%, P < .01) and less asynergy i n the chronic phase (19.9 +/- 15.6% vs 46.5 +/- 14.0%, P < .01) than p atients with a QTd(1) of less than 0.1 second. Thus, QT dispersion in the acute phase of anterior myocardial infarction indicates recovery o f left ventricular wall motion. Prolongation of the local action poten tial duration of the myocardium that recovers from severe ischemia may be a contributor to the increased QT dispersion that results in inver sion of T waves in the acute phase of myocardial infarction.