We describe here our experience with a neonate presenting with cyanosis, grunting, and cardiome galy, who was diagnosed with isolated left ventricular noncompaction (IVNC) by echocardiography. The patient had high levels of N-terminal pro-B-type natriuretic peptide (NT pro-BNP) and symptoms of heart failure including poor feeding and tachypnea. During the period in which NT pro-BNP levels steadily increased, the patient suffered sudden cardiac arrest despite heart failure management. Following cardiopulmonary resuscitation, cardiac arrest was resolved, NT pro-BNP levels decreased, and all symptoms showed improvement. We consider that assessment of NT pro-BNP with cardiac functional analysis using echocardiography could help in the prediction of disease progress in IVNC.