Giant Intramural Left Ventricular Rhabdomyoma in a Newborn

A 1-day-old newborn was referred with prenatal echocardiographic diagnosis of cardiac mass. Born by caesarean section at 38+3 weeks of pregnancy, he presented with cyanosis and bradycardia at birth, requiring immediate intubation and mechanical ventilation. Chest x-ray demonstrated cardiomegaly with a cardiothoracic index of 0.7 (Figure 1). Echocardiographic examination (Figure 2 and Movie I in the online-only Data Supplement) confirmed the diagnosis of a large cardiac mass located at the posterior wall and at the apex of the left ventricle (LV). The child presented with several episodes of paroxysmal supraventricular tachycardia, which were treated with DC shock and various pharmacological agents, such as amiodarone, adenosine, flecainide, digoxin, and metoprolol, and 1 episode of ventricular fibrillation with cardiac arrest requiring resuscitation. MRI showed a single large mass (5.5×5 cm) arising from the left atrioventricular groove and extending to the LV lateral wall and apex, up to the interventricular septum, with no LV inflow or outflow obstruction, and was suggestive …