A PROMINENT EUSTACHIAN VALVE MIMICKING COR TRIATRIATUM DEXTRUM

Persistent Eustachian valve (EV) is a rare congenital anomaly resulting from incomplete regression of the embryonic right sinus venosus valve. Although typically regressing during childhood, its persistence into adulthood is uncommon. We report a case of a young female with a history of rheumatic heart disease and prior percutaneous trans-mitral commissurotomy (PTMC) who presented with dyspnoea. Transthoracic echocardiography (TTE) revealed a large membranous structure consistent with a persistent EV, which mimicked Cor triatriatum dextrum (CTD) by dividing the right atrium (RA) into two chambers. Transesophageal echocardiography (TEE) could not be performed due to patient refusal, limiting detailed evaluation. While often asymptomatic, a persistent EV can lead to complications such as paradoxical thromboembolism, endocarditis, and difculties with cardiac catheterization. Recognizing this anatomical variant is crucial for accurate diagnosis and management, particularly in interventional procedures or in the presence of thromboembolic events. Although some cases may require surgical intervention, this patient's condition did not necessitate active treatment. This case underscores the importance of distinguishing a persistent EV from CTD and understanding its clinical implications for appropriate management.