Atrial dissociation: an electrophysiologic finding in a patient with transposition of the great arteries

Complete interatrial block with two independent atrial rhythms is demonstrated by intracardiac electrograms in a patient with transposition of the great arteries who had undergone a Mustard operation. The atrial conduction abnormalities produced by the Mustard procedure with subsequent baffle revision are related to damaged anatomic interatrial connections and are similar to conduction abnormalities produced in experimental models of interatrial block.