SOLVING A BIG ISSUE
OF A LITTLE HEART

Untiring team effort cures a sick newborn with
cardiac rhythm disorders

A 16-day-old, sick child was brought to BLK Super Speciality Hospital with a history of persistently increasing heart rate (tachycardia with HR of 300/ min). The patient was on ventilator in a shock state. The baby was admitted to NICU. Evaluation of cardiac rhythm showed that the baby was in Supraventricular Tachycardia (SVT, ECG A). The baby's weight at the time of admission was just 3.9 kilogram. Echo result showed normal cardiac anatomy with severe left ventricular dysfunction.

Immediately after securing external jugular vein access, 3 doses of adenosine were given. However, there was no response. Subsequently, direct current synchronized cardioversion (DC cardioversion) was given (4 joules and 8 joules). Still, there was no response, and the patient remained in SVT rhythm.

Loading doses of metoprolol (0.4 mg) and amiodarone (5 mg/kg) were

given after which the baby regained normal sinus rhythm. Following this, maintenance doses of these two medicines were started. After an hour, the same tachyarrhythmia re-occurred with HR of 300/min. Oral flecainide was started along with metoprolol and amiodarone injections, and normal sinus rhythm was achieved again. The following day, ECG was done which showed a long QT interval (QTc: 0.57 sec). As a result, flecainide and amiodarone were discontinued as both these medications cause long QT interval.

Electrophysiology consultation was sought which hinted that the abnormal rhythm could probably be due to pre-excitation (WPW syndrome). The patient was advised to stop metoprolol and to start with esmolol injection. The same evening, SVT happened again. Consequently, boluses of metoprolol and amiodarone were given and rhythm was reverted to normal sinus rhythm. The same medications were continued along with metoprolol and amiodarone infusion. Esmolol was stopped. The next day, long QT happened again, as a result amiodarone was stopped, and metoprolol infusion (3mcg/kg/min) was continued. There was no further episode of SVT. Propranolol tablet was started. After a 24 hour observation, metoprolol injection was tapered over the next 3-4 days. The patient was extubated on the 3rd day.

The baby was discharged on oral propranolol. Pre-discharge tests showed normal left ventricle function on echocardiography and normal sinus rhythm along with normal QT interval in ECG B.