Neonatal Supraventricular Tachycardia (SVT)

Abstract

A male neonate born at 31 weeks’ gestation had a history of fetal supraventricular tachycardia (SVT) detected at 28 weeks’ gestation, with no hydropic changes noticed on ultrasonography. The mother was started on enteral digoxin with instructions for weekly follow-up. On her first return visit at 31 weeks’ gestation, ultrasonography revealed hydropic changes and persistent SVT. An emergency cesarean section was performed, and the infant was found to have hydrops and respiratory distress, with a heart rate of 270 beats/min. The patient was intubated and mechanically ventilated and received a dose of intravenous (IV) adenosine, resulting in a transient decrease in heart rate to 120 beats/min before increasing back to 260 to 270 beats/min. SVT persisted despite institution of an esmolol drip at 500 mcg/kg per minute, and cardioversion was performed when hemodynamic instability developed. Recurrent SVT, associated with hypotension, developed within 45 minutes of successful cardioversion. The patient was given a loading dose of amiodarone, followed by cardioversion, continuous amiodarone, and dobutamine infusion. Echocardiography revealed normal anatomy with moderately reduced function. The patient remained in sinus rhythm and was weaned to oral amiodarone after 1 week of infusion. An echocardiogram revealed normal function. The patient was discharged from the hospital receiving 3 mg/kg per day of oral amiodarone. SVT is the most common symptomatic arrhythmia in childhood that can be a recurrent and persistent condition. The quoted incidence of SVT in children of 1 in 25,000 is based on an estimate made in 1967, (1) but with a higher index of suspicion and better methods of detection, it now is estimated to be 1 in 100 for children of all ages and 1 in 200 to 250 for neonates. (2) We report a case series of seven patients admitted to our neonatal nursery recently who had a diagnosis of …