Successful catheter ablation in an octogenarian with persistent atrial fibrillation complicated by cor triatriatum sinister: a case report.

Background: Cor triatriatum sinister (CTS) is a rare congenital heart defect sometimes complicated with atrial fibrillation (AF). Catheter ablation (CA) relieves the AF-associated symptoms, but CA for AF with CTS has been reported rarely. Because CTS can be associated with other congenital heart disease, detailed preoperative assessment is important. Case summary: An 80-year-old man was referred to our institution for shortness of breath that had persisted for 2 months when he was first diagnosed with AF. Transthoracic echocardiography revealed an enlarged left atrium (LA) divided into two chambers by a membrane. Transoesophageal echocardiography showed the membrane extending from the fossa ovalis (FO) to the Coumadin ridge, with the accessory (dorsal) chamber (AC) in closer proximity to the FO. Computed tomography showed that all pulmonary veins (PVs) flowed into the AC, with no PV anomalies. No other heart anomaly was identified, with no thrombus in the LA. With these findings, PV isolation (PVI) with CA was considered safe. Transseptal puncture was performed with intracardiac echocardiography for precise catheterization of the AC. Pulmonary vein isolation was performed successfully. The patient was discharged 4 days after the procedure, without any complications. His symptoms improved post-procedure, and sinus rhythm was maintained without antiarrhythmic drug therapy during the 18-month follow-up. Discussion: Cor triatriatum sinister is a rare anomaly that accounts for 0.1% of all congenital heart diseases. Cor triatriatum sinister sometimes complicated with symptomatic AF. Detailed preoperative anatomical assessment with multiple imaging modalities helped us achieve safe and effective CA for a patient with AF and CTS, even in an octogenarian.