A 52-year-old man presented to an emergency department with a 1-month history of chest tightness and respiratory asphyxia that exacerbated within the last 2 hours. He additionally had a 30-year history of exertional palpitations. Physical examination revealed cyanosis of the lips, irregular, accelerated heart rate, and a systolic murmur in the area of the mitral valve on auscultation. The right and left superior and inferior pulmonary veins converged into the pulmonary vein trunk (Supplementary material, Figure S1). Computed tomography angiography revealed abnormal communication between the pulmonary venous trunk and the superior vena cava, with the pulmonary vein ultimately draining into the right atrium (Figure 1A and 1B). Ultrasonography indicated the presence of an atrial septal defect as well as evidence of a bidirectional shunt between the left and right atrium (Figure 1C and 1D).

Figure 1. A, B – virtual reality (A) and sagittal plane (B) images revealed that the pulmonary vein trunk (PVT) communicates with the superior vena cava (SVC) and ultimately drains into the right atrium (RA). C – echocardiography revealing the presence of an atrial septal defect; D – color Doppler imaging exhibiting the existence of a bidirectional shunt between the RA and left atrium (LA).

Based on these findings, the patient was diagnosed with supracardiac total anomalous pulmonary venous connection (TAPVC). Virtually all cases of TAPVC occur in infants, and the mortality rate by the age of 12 months in untreated cases is 80%.1 Diagnoses of this condition in older adults are extremely rare. In the present case, the left atrium did not receive any direct pulmonary venous return, while the right atrium received systemic venous return, resulting in the right atrial enlargement.2 We speculate that the bidirectional shunt observed between the left and right atrium would compensate for these abnormalities over the course of several decades, and that it may be the key to the survival of patients exhibiting cardiovascular developmental abnormalities.3 This is supported by the color Doppler results and ejection fraction score (69%) for this patient. After his symptoms were alleviated through medical treatment, the patient was discharged home, and he has remained stable on follow-up after 6 months.