Epicardial activation-to-repolarization coupling differs in the local areas and on the entire ventricular surface

Hypothesis: local and global activation-to-repolarization coupling differ from each other.Experiments were done in 12 dogs and 7 frogs. Activation times (ATs), end of repolarization times (RTs), and activation-recovery intervals (ARIs) were measured in 24 or 64 leads on the entire ventricular surface and on the epicardial patch 5 × 5 mm.The ARI and RT dispersions were greater than AT dispersion on the entire ventricular epicardium but not in the local patch. Both ATs and ARIs were inversely related to each other in the patch but not necessarily on the entire epicardium. The RT sequence depended on the AT sequence within the local patch but not on the entire surface. The contributions of the AT sequence and ARI distribution to the RT sequence was determined by the AT/ARI dispersion ratio.Thus, the AT sequence strongly influenced the RT sequence of the local epicardial fragment but not of the entire ventricular surface.