An unusual cause of pulmonary hypertension; partial anomalous pulmonary venous return to coronary sinus detected on transesophageal echocardiography

An asymptomatic male patient aged 25 years was admitted to the cardiology polyclinic with two transesophageal echocardiography (TEE) reports from separate hospitals indicating no abnormalities. Transthoracic echocardiography revealed mild tricuspid valve regurgitation and mild right chamber dilation. Mean pulmonary arterial pressure measured on pulmonary valve was 37 mm Hg. Coronary sinus (CS) was dilated with an abnormal flow (Fig. 1a, 1b). TEE was performed to detect the etiology of pulmonary hypertension (PHT); it showed that the left upper pulmonary vein was separated from the left atrium by a septum (Video 1) and the left upper and lower pulmonary veins were both draining to the CS (Fig. 1c, 1d, Video 2). Computed tomography showed partial anomalous pulmonary venous return (PAPVR) that involved left pulmonary veins draining into CS, as seen on TEE (Fig. 2). The patient was referred for right cardiac catheterization and subsequent surgical correction, although the procedure has not yet been performed.