Typical atrial flutter in an atypical patient.

Arrhythmias in adult congenital heart disease (ACHD) pose unique procedural challenges, especially with intravascular access. We report a unique case of ablation via a left-sided hepatic vein approach in a patient with situs inversus totalis. A 28-year-old woman with situs inversus totalis, ventriculoseptal defect, and dextro-transposition of the great arteries underwent ablation for documented narrow-complex tachycardia. Because of bilateral iliac venous occlusions, the coronary sinus (CS) was accessed through the left internal jugular vein. Rapid atrial pacing resulted in a tachycardia with an atrial cycle length of 225 msec and 2:1 atrioventricular association. Entrainment from the proximal and distal CS was consistent with typical atrial flutter around the left-sided tricuspid valve. Because of the iliac vein occlusions, access for ablation was obtained via a left-sided hepatic vein (Figure 1). Resetting from the cavotricuspid isthmus and three-dimensional electroanatomic mapping (Figure 2) confirmed typical atrial flutter, which, given the dextrocardia, occurred in a clockwise fashion around the tricuspid valve. Ablation was performed at the cavotricuspid isthmus resulting in arrhythmia termination and isthmus block. This case highlights the many unusual challenges that patients with ACHD can pose to the proceduralist, including atypical cardiac anatomy and difficult intravascular access. Unusual and creative approaches are often necessary to treat these patients successfully.