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Case Reports in Medicine
Volume 2014, Article ID 674018, 5 pages
Case Report

Cor Triatriatum Sinister Identified after New Onset Atrial Fibrillation in an Elderly Man

1Department of Medicine, University of California San Diego, La Jolla, CA 92161, USA
2Division of Cardiovascular Medicine and Sulpizio Family Cardiovascular Center, University of California San Diego, 9434 Medical Center Drive, La Jolla, CA 92037, USA

Received 18 August 2014; Revised 5 December 2014; Accepted 8 December 2014; Published 29 December 2014

Academic Editor: Simon Ching-Shun Kao

Copyright © 2014 Ignacio A. Zepeda et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


A 73-year-old man with new onset atrial fibrillation with rapid ventricular response underwent transthoracic echocardiography that revealed an echogenic linear structure along the left atrium, suggestive of cor triatriatum sinister (CTS). CTS was confirmed with transesophageal echocardiography which demonstrated a proximal accessory atrium receiving pulmonary venous flow separated from a distal true atrium by a fibromuscular membrane with a large fenestration allowing flow between the chambers. In CTS, the left atrium is divided into proximal and distal chambers by a fenestrated fibromuscular septum. This cardiac anomaly accounts for 0.1% of cases of congenital heart disease and rarely presents in adults. CTS is primarily diagnosed with echocardiography and is associated with left atrial enlargement and development of atrial fibrillation. Treatment options depend on size of the communication between proximal and distal chambers, the gradient across the membrane, and the position of pulmonary veins. In some instances, surgical resection of the membrane that divides the left atrium is warranted.