Atypical presentation of ALCAPA in a young boy: a case report.

Anomalous origin of the left main coronary artery from the pulmonary artery (ALCAPA) is a rare congenital cardiovascular defect in young children. It is typically diagnosed through direct visualisation of the left coronary artery arising from the main pulmonary artery or observing retrograde flow from the left coronary artery to the main pulmonary artery at angiography or echocardiography. This case highlights the diagnostic challenges of ALCAPA in young kids, where antegrade left coronary artery flow due to pulmonary hypertension masked the anomalous origin on echocardiography. Despite the absence of congenital shunts, long-term severe mitral regurgitation led to pulmonary hypertension, presenting with atypical imaging features. The boy accepted a successful surgical reimplantation of the left coronary artery to the aorta with concomitant mitral valve repair and had significant resolution of symptoms.