Spatio-temporal features of variability repolarization during acute myocardial ischemia

Abstract

Several studies have shown that dynamic variability of ventricular repolarization morphology is associated with an increased risk for developing ventricular arrhythmias. We evaluated beat-to bea ventricular repolarization variability using the T-wave spectral variance (TSV) index during acute myocardial ischemia from the spatial electrocardiogram ECG planes. The study group consisted of 71 patients in which the three orthogonal XYZ leads were obtained during both control (5 min.) and percutaneous coronary intervention (4 min. 36 sec. ± 80 sec.) of different arteries. Three spatial ECG planes were determined: the frontal plane (FP) defined by XY-leads, the horizontal plane (HP) defined by XZ-leads and the sagittal plane (SP) defined by YZ-leads. Results indicated that the TSV index has shown the most important significant differences with respect to control in: FP to the left anterior descending coronary artery occlusion (p < 0.001 in X-lead; p < 0.0001 in Ylead), HP to the right coronary artery occlusion (p < 0.001 in Y-lead; p < 0.0001 in Z-lead) and SP to the left circumflex coronary artery occlusion (p < 0.01 in Xlead; p < 0.01 in Z-lead). We conclude that TSV index offers a robust tool for evaluating beat-to-beat repolarization variability during acute ischemia, which depends on the link between the occluded artery and the analyzed ECG plane.