The anomalous origin of the left coronary artery from the pulmonary artery, also known as ALCAPA syndrome or as Bland-White-Garland syndrome, is a rare cardiac disorder. Because it causes myocardial ischemia, this syndrome can contribute to the development of ischemic cardiomyopathy, with congestive heart failure in the first months of life. In this pathology, the coronary artery with an abnormal origin has lower myocardial perfusion pressure and blood with lower oxygen concentration because it originates directly from the pulmonary artery, which can lead to a clinical picture of myocardial dysfunction and neonatal death. In this context, this article aimed to report the case of a patient who was diagnosed with anomalous origin of the left coronary artery from the pulmonary artery and developed complications with serious clinical repercussions.