Dissimilar atrial rhythms. A patient with interatrial block.

Abstract

A patient with type A Wolff-Parkinson-White syndrome and prolonged interatrial conduction intervals developed atrial flutter during the course of an electrophysiological study. The atrial flutter blocked along the left-to-right conduction pathways in a Wenckebach pattern. The dissimilar atrial rhythms of right atrial tachycardia and left atrial flutter evolved as the interatrial block increased to 2:1 conduction.