Dual-loop intra-atrial re-entry tachycardia in a patient with ischaemic cardiomyopathy.

A 65-year-old man with ischaemic cardiomyopathy (three prior coronary artery bypass surgery procedures), underwent catheter ablation for recurrent atrial flutter. Electrophysiological study initially revealed clockwise, tricuspid annulus/inferior vena cava isthmus dependent, atrial flutter. During radiofrequency energy ablation atrial flutter changed into a different atrial tachycardia without change in cycle length or interruption of the tachycardia. The new tachycardia was a right atrial free wall re-entry tachycardia. Thus the two atrial tachycardias formed a dual-loop ('figure-of-eight') re-entry circuit, possibly due to atrial scar tissue from multiple cardiac surgery procedures.