PO-04-079 FIRING EXTRA CHAMBERS: COR TRIATRIATUM SINISTER WITH ATRIAL FIBRILLATION

Abstract

Cor triatriatum sinister (CTS) is a rare congenital defect in which the left atrium is divided into two chambers by a fenestrated fibromuscular septum. It is found in less than 0.1% of clinically diagnosed cardiomyopathy and 0.4% of autopsies of congenital heart disease patients. Dyspnea was reported as the most common symptom and atrial fibrillation (AF) was described in 30% of the published cases of CTS. We report a young patient with CTS who had recurrent paroxysmal atrial fibrillation (PAF) that underwent standard radiofrequency (RF) pulmonary vein isolation (PVI). 1. To recognize the relation of a rare congenital anomaly to AF 2. Effectiveness of standard PVI in CTS with AF NA A 39-year-old male was referred for symptomatic PAF with CHAD2VASc score of 3. Medical history was significant for CTS, tachybrady syndrome status post leadless pacemaker, diabetes, hypertension, HFpEF, and sleep apnea on CPAP. Pertinent medications were rivaroxaban, diltiazem and metoprolol. AF burden could not be determined. Echocardiogram revealed LA volume of 119 ml, CTS with volume index 52ml/m2 with an opening of 0.8 cm2 and moderate mitral regurgitation with valve area 2.9cm2, PHT 77 ms. Right heart cath showed PAP 50/30 mmHg, PCWP 30 mmHg and PVR 0.8 Woods unit. Cardiac index was 3.5L/min/m2. Despite optimization of rate control therapy and DC cardioversion, the patient had recurrent debilitating AF and decided to undergo RF AF ablation. Intracardiac echo showed the membrane to be attached to the posterolateral ridge laterally and to the interatrial septum medially. Voltage mapping revealed a healthy posterior wall. PVI was achieved successfully with first pass ablation. Patient maintained sinus rhythm at the 3 months follow up. CTS was first described in 1868 by Church. Development of AF from CTS in adults can be related to calcification of the membrane fenestrations leading to mitral stenosis and eventual development of mitral regurgitation with aging.