Changes of basic ECG parameters of ventricular repolarization during coronary occlusion. (A) The representative QRST complexes in the leads with maximal (V3) and minimal, if any (V5), ST-segment displacement during the course of LAD occlusion. Automatically measured margins of QRS complexes and markers for the T_peak and T_end are indicated by the short vertical lines and circles, respectively. Note the increased dispersion of T_peak timing (long vertical lines) due to QT_peak shortening in V3. (B) The time course of repolarization duration indices (averaged durations of maximal and minimal QTc and QTc_peak intervals). (C) The time course of repolarization heterogeneity indices (averaged values of T_peak-T_end interval, QTc dispersion and QTc_peak dispersion) ^††P < 0.01 vs. baseline; ^†††P < 0.001 vs. baseline. LAD, left anterior descending coronary artery.