The “Well-Appearing Trap”: Cardiac Point-of-Care Ultrasound (POCUS) Prompting the Diagnosis of Anomalous Left Coronary Artery From the Pulmonary Artery (ALCAPA)

Anomalous left coronary artery from the pulmonary artery (ALCAPA) is a rare congenital coronary anomaly associated with high mortality when left untreated.A key diagnostic pitfall of ALCAPA is that infants may appear relatively well despite profound underlying myocardial dysfunction, creating a "well-appearing trap."To address this risk, bedside point-of-care ultrasound (POCUS) can be employed to identify occult ventricular dilation and dysfunction, prompting definitive cardiac evaluation.We describe two infants with ALCAPA who presented to our emergency department: a nine-month-old boy with a 12-hour history of decreased urine output and a two-month-old girl with a one-day history of inconsolable crying.In both patients, cardiac POCUS revealed marked left ventricular dilation and severely reduced systolic function that were not apparent from their initial clinical appearance, prompting urgent definitive cardiac imaging.These cases highlight a central diagnostic challenge: infants may appear relatively stable while harbouring lifethreatening myocardial dysfunction.Cardiac POCUS provides a rapid bedside means of recognizing this clinical-structural mismatch, identifying occult ventricular dysfunction, and accelerating definitive cardiac assessment.