Tachycardia-Induced Cardiomyopathy in ccTGA

BACKGROUND: Incessant atrial tachycardia (AT) in patients with heart failure and congenitally corrected transposition of the great arteries (ccTGA) is rare and challenging for ablation. CASE SUMMARY: A 49-year-old man with ccTGA and membranous ventricular septal aneurysm presented with incessant AT leading to heart failure, refractory to antiarrhythmic drugs and electrical cardioversion. Initial extensive atrial mapping suggested the left atrial anterior wall as the site of earliest activation, but ablation at this site was ineffective. Computed tomography reconstruction and intracardiac echocardiography (ICE) suggested a close anatomical relationship between the suspected focus and the pulmonary sinus cusp. ICE facilitated safe advancement of the ablation catheter to the pulmonary artery root while avoiding interference with the membranous ventricular septal aneurysm. Subsequent mapping in the pulmonary artery root identified the right sinus cusp as the critical site, where ablation successfully terminated the tachycardia. At 6-month follow-up, the patient remained free of arrhythmia with marked improvement in cardiac function. DISCUSSION: Mapping beyond the conventional atrial chambers may be required for AT in patients with ccTGA owing to the unique anatomic characteristics. The pulmonary sinus cusps may serve as an alternative access point for ablation of adjacent atrial tissue in ccTGA. Imaging with 3-dimensional computed tomography reconstruction and ICE can provide complementary information to delineate the relationship between the pulmonary sinus cusp and adjacent atrial structures. TAKE-HOME MESSAGES: In patients with ccTGA and AT, pulmonary sinus mapping may provide an effective ablation target due to altered anatomy. Comprehensive imaging is essential for safe ablation in complex anatomy.