Background
Cor triatriatum sinister represents a rare congenital left atrial malformation associated with complex anatomical conditions for catheter ablation. Published experience with pulsed field ablation in CTS remains extremely limited and has largely been restricted to isolated case reports.
Case Summary
A patient with symptomatic paroxysmal atrial fibrillation and recurrent typical atrial flutter after previous cavotricuspid isthmus ablation was referred for left atrial ablation. Preprocedural imaging using transesophageal echocardiography and contrast-enhanced CT demonstrated CTS with suspicion of a left common pulmonary vein trunk and close anatomical proximity to the esophagus. Given the complex left atrial anatomy, a PFA-based strategy was chosen. Transseptal puncture was performed under TEE guidance with access to the pulmonary venous compartment. Detailed 3D mapping of both left atrial compartments was performed using the Affera Sphere-9 catheter. Vein-mode reconstruction did not confirm a true left common pulmonary vein trunk despite the initial CT appearance. Wide antral pulmonary vein isolation using PFA was successfully completed without complications. In addition, reconnection of the CTI line was identified and successfully reablated using radiofrequency energy until bidirectional block was achieved. Procedure time was 94 minutes with fluoroscopy time of 1.9 minutes. Postprocedural course was uneventful without recurrence of atrial fibrillation or atrial flutter during follow-up.
Discussion
This case highlights the importance of compartment-oriented mapping in CTS and demonstrates the feasibility of PFA in complex left atrial anatomy. Furthermore, the case illustrates potential discrepancies between preprocedural CT morphology and intraprocedural electroanatomic reconstruction in CTS.
Conclusion
PFA combined with structured high density 3D electroanatomic mapping may represent a safe and effective strategy for pulmonary vein isolation in patients with CTS and complex left atrial anatomy.
