Dispersion of ventricular repolarization: Temporal and spatial

Figure 1 Transmembrane action potential and pseudo electrocardiogram recordings from a canine arterially perfused ventricular wedge preparation reveal the cellular basis for the T wave. Top: Action potentials simultaneously recorded from endocardial, epicardial, and M region sites; Bottom: Electrocardiogram recorded across the wedge; the peak and the end of T-wave correspond to the end-of-repolarization of epicardial and M-cells, correspondingly. Compiled from Figure 2[8]. ECG: Electrocardiogram.

Figure 2 Realistic activation sequence, action potential duration distribution and end-of-repolarization sequence in the rabbit heart ventricles’ model, simulated from intramural and epicardial measurements[56]. The middle transversal and longitudinal cross-sections of the model and the corresponding T-vector projections are shown. Transmural, apicobasal, anterior-posterior and left-to-right gradients in activation times, action potential duration and end-of-repolarization times, reconstructed from experimental data, are presented. A and B – the regions of the earliest and the latest end-of-repolarization, correspondingly. T-vector direction is parallel but opposite to the general direction of repolarization sequence.