Repolarization Phase at Various Sites of the Right Atrium

Abstract

By means of a suction electrode method, the time course of depolarization and repolarization was observed in the in situ exposed right atrium of dogs. Under normal conditions the end of repolarization at various sites on the atrium occurred after the QRS spikes, and therefore, the T_a wave should be inscribed after and not during the QRS spikes. The concentric spread of activation originating from the S-A node has been confirmed. The region of inital excitation does not become the initial focus of repolarization. The initial focus of repolarization is different from animal to animal, and this focus cannot be associated with any special cardiac tissue. The process of repolarization occurs concentrically from an initial focus that is not limited to any specific region of the atrium.