[First diagnosis of ALCAPA syndrome in adulthood: a rare cause of cardiac arrest].

A 42-year-old patient with return of spontaneous circulation (ROSC) following an out-of-hospital cardiac arrest was referred to the authors' emergency department. The initial rhythm was ventricular fibrillation. A computed tomography scan and subsequent coronary angiography revealed anomalous left coronary artery from the pulmonary artery (ALCAPA) syndrome as the cause of this condition. A thickened right coronary artery with significant collateral blood flow to the left coronary artery was observed. After initial treatment in the authors' intensive care unit, surgical intervention was performed. The patient was discharged from hospital without any neurological damage.