Transient repolarization alterations dominate the initial phase of an acute anterior infarction - a vectorcardiography study

ObjectiveTo study effects of ischemia-reperfusion on ventricular electrophysiology in humans by three-dimensional electrocardiography.MethodsFifty-seven patients with first-time acute anterior ST elevation myocardial infarction were monitored from admission and > 24 h after symptom onset with continuous vectorcardiography (VCG; modified Frank orthogonal leads). Global ventricular depolarization and repolarization (VR) measures were compared at maximum vs. minimum ST vector magnitude (STVM) (median 208; 111-303 vs. 362; 165-1359 min after symptom onset).ResultsAt maximum vs. minimum STVM the Tarea (overall VR dispersion) almost tripled (118 vs. 41 μVs; p < 0.0001), the T-loop bulginess was 90% greater (Tavplan 0.91 vs 0.48 μV; p < 0.0001), and Tpeak-end/QT was 39% larger (0.32 vs 0.23; p < 0.0001). QRSarea (overall dispersion of depolarization) was 12% larger at maximum STVM, while QRS duration was 10% longer at minimum STVM.ConclusionsIschemia-reperfusion was accompanied by profound and transient alterations of VR dispersion, while changes in depolarization were modest and delayed.