A Rare Case of an Unroofed Coronary Sinus With a Persistent Left Superior Vena Cava Diagnosed by Two-Dimensional Transthoracic Echocardiography

An unroofed coronary sinus is a rare congenital anomaly in the roof of the coronary sinus causing a communication between the coronary sinus and the left atrium leading to a left to right shunt. It is often associated with a persistent left superior vena cava and other complex congenital lesions like anomalous pulmonary venous return and heterotaxy. Since it is a deep-seated defect, it is seldom diagnosed by transthoracic two-dimensional (2D) echocardiography and requires multimodal imaging for a diagnosis. Here, we present the case of a 27-year-old male in whom the defect was very apparent on standard 2D transthoracic echocardiography. Transthoracic 2D echocardiography revealed situs solitus, levocardia, and a dilated coronary sinus with unroofing which was most prominent in the standard parasternal long-axis view and the foreshortened apical four-chamber view. A color Doppler demonstrated a flow from the left atrium into the dilated coronary sinus. The right ventricle and atrium were dilated with mild pulmonary arterial hypertension. There was no right ventricular dysfunction. Examination with modified suprasternal views showed a left superior vena cava. All four pulmonary veins drained into the left atrium. Other chambers of the heart and great vessels were structurally normal without coarctation or patent ductus arteriosus. The interventricular septum was intact and atrioventricular and ventriculoatrial concordance was preserved. Detection of a dilated coronary sinus by transthoracic 2D echocardiography must be followed by multimodal imaging techniques like cardiac computed tomography and transesophageal echocardiography to detect and manage associated defects.