Echogenic cardiac mass in the left atrium and associated supraventricular tachycardia in a neonate

Abstract

Introduction. Primary cardiac tumors in children are rare and the majority of them are diagnosed before the age of one year. They are mainly rhabdomyomas and have a tendency to regress. The incidence of arrhythmias is not well-defined, depending on the size and location of tumors. Case outline. The authors report a female neonate with ongoing fetal supraventricular tachycardia (SVT). Delivery by urgent cesarean section was performed with neither fetal echocardiography nor fetal antiarrhythmic drug intervention. Electrocardiogram confirmed tachycardia with narrow QRS complex at a rate of 260 beats/min. converting to sinus rhythm after a third dose of intravenous bolus injection of adenosine-5?-triphosphate. But the rhythm reverted to SVT showing refractory supraventricular reentrant tachycardia. Echocardiography performed after conversion to sinus rhythm showed an echogenic, well circumscribed mass in the left atrium, fixed to the primum atrial septum without other structural defects. SVT was treated by a bolus of amiodarone followed by an intravenous infusion. Long-term management with oral amiodarone and beta blocker had a good response. During the one-year follow-up echocardiograms were performed every month showing complete regression of cardiac mass, and there has been no recurrence of tachycardia since neonatal period. Conclusion. Tumor regression and a good long-term outcome in our patient suggest that it was probably a small but unfavorably positioned rhabdomyoma, associated with fetal and perinatal SVT. Prognosis and outcome of the disease depends on timely diagnosis and prompt and adequate treatment of associated life-threatening arrhythmias.