Abstract
BACKGROUND: Crossed pulmonary arteries or single atrium is a rare form of cardiovascular anomaly. In previous studies, the anomalies are detected in infant or early adolescence, and infrequently seen in adult population. CASE PRESENTATION: We presented a case of the coexistence of two congenital anomalies in a 44-year-old woman who remained well tolerated and undiscovered until adulthood. Physical examination showed a grade III systolic murmur at the cardiac apex, and a grade II/III systolic murmur at left 2-3 intercostal space. An echocardiography revealed absence of atrial septal tissue. Dual-source CT angiography was performed for further evaluation of the great vessel. Except an enlarged single atrium, the imaging showed that the origination of the left pulmonary artery from the pulmonary trunk was superior to that of the right pulmonary artery. The branch pulmonary arteries then crisscrossed as they coursed to their respective lungs. The findings were illustrated by the right heart catheterization and then confirmed at surgery. CONCLUSIONS: To our knowledge, this is the first case report of crossed pulmonary arteries with single atrium as the only additional cardiac anomaly in an adult. Knowledge of this rare combination will be helpful in the differential diagnosis of congenital heart disease and assist the surgeon in treatment planning.