Right atrial tachycardia in a patient with severe atrial conduction disturbances and an anatomically normal heart.

We describe a case of abnormal right atrial (RA) conduction in a patient with atrial tachycardia (AT) but no history of structural heart disease or cardiac surgery. Following ablation of AT, the patient experienced typical atrial flutter (AFL) and a postcardioversion ECG suggestive of low atrial rhythm. Repeat EPS and three-dimensional electroanatomic activation mapping showed unusual RA activation during SR. This case illustrates the possibility that abnormal intraatrial conduction may lead to unusual patterns of activation in the RA which can serve as a necessary substrate for the initiation and maintenance of macro-reentry circuits.