Transesophageal echocardiography identified cor triatriatum sinister in a 56-year-old female presenting with unexplained arrhythmias and heart failure symptoms.
Case Report (n=1)
Cor triatriatum sinister can remain undiagnosed until adulthood and should be considered in the differential for unexplained arrhythmias or heart failure, with advanced imaging like TEE being critical for diagnosis.
Abstract Background Cor triatriatum is a rare congenital cardiac anomaly characterized by a fibromuscular membrane dividing an atrium into two chambers. While typically diagnosed in infancy or childhood due to significant hemodynamic compromise, some cases remain undetected until adulthood, particularly when the membrane is large or fenestrated, allowing relatively unobstructed blood flow. Adult presentations are uncommon, making recognition challenging and highlighting the importance of maintaining a broad differential in patients with unexplained arrhythmias or heart failure. Case Summary A 56-year-old female presented with several weeks of palpitations and progressively worsening exertional dyspnea. She denied chest pain, orthopnea, paroxysmal nocturnal dyspnea, or peripheral edema. Her medical history included prior myocardial infarction treated with percutaneous coronary intervention, chronic heart failure, hypertension, hyperlipidemia, chronic obstructive pulmonary disease, anxiety, depression, and atrial fibrillation successfully treated with electrical cardioversion one year prior. Transthoracic echocardiography revealed preserved left ventricular function (LVEF 55-65%) and grade I diastolic dysfunction. Persistent symptoms prompted transesophageal echocardiography, which demonstrated a fibromuscular membrane dividing the left atrium, consistent with cor triatriatum sinister (CTS). She was referred for cardiothoracic surgical evaluation and scheduled for cardiac MRI for further anatomical delineation. Discussion CTS accounts for 0.1-0.4% of congenital cardiac anomalies and can coexist with other structural defects. The postero-superior chamber receives pulmonary venous return, while the infero-anterior chamber communicates with the mitral valve, often mimicking mitral stenosis. In adults, symptoms may emerge late due to minimal obstruction across the membrane. Advanced imaging, including TEE and cardiac MRI, is critical for accurate diagnosis and surgical planning. Definitive management involves surgical excision of the membrane, which is associated with favorable long-term outcomes. Medical therapy including rate/rhythm control, anticoagulation, and diuretics can provide symptomatic relief while awaiting surgery. This case underscores that congenital anomalies like CTS may remain undiagnosed into adulthood and should be considered in adults presenting with unexplained arrhythmias or heart failure symptoms. Early recognition using advanced imaging allows timely intervention, alleviates symptoms, and prevents complications. (A-B) Two-dimensional mid-esophageal views show a thin fibromuscular membrane dividing the left atrium (LA) into a proximal (LA1) pulmonary venous chamber and a distal (LA2) true atrial chamber that communicates with the mitral valve (MV) and left ventricle (LV). (C) Color Doppler imaging demonstrates turbulent flow through a small fenestration in the membrane, confirming hemodynamic obstruction between the two atrial chambers. RA, right atrium; IAS, interatrial septum. This abstract is funded by: None
Sherpa et al. (Fri,) conducted a case report in Cor triatriatum sinister (n=1). Transesophageal echocardiography was evaluated. Transesophageal echocardiography identified cor triatriatum sinister in a 56-year-old female presenting with unexplained arrhythmias and heart failure symptoms.