Case Report: Catheter ablation of atrial fibrillation in a patient with cor triatriatum sinistrum: the pivotal role of intracardiac echocardiography and electroanatomic mapping.

Cor triatriatum sinister (CTS) is a rare congenital cardiac anomaly that presents significant challenges for catheter ablation of atrial fibrillation (AF) due to its complex left atrial anatomy. We report the case of a 47-year-old man with persistent AF and CTS who successfully underwent radiofrequency catheter ablation. Intracardiac echocardiography was critical in guiding transseptal puncture and delineating the atrial chambers, while electroanatomic mapping revealed a high-voltage area rather than a low-voltage zone at the fibromuscular membrane. This case underscores the importance of advanced imaging and individualized ablation strategies in managing arrhythmias in structurally abnormal hearts.