Incidentally Detected Supraventricular Tachycardia in a Preterm Neonate: A Case Report of Successful Medical Management and Follow-up

Abstract

The neonatal or newborn period is defined as the time interval between birth and the twenty-eighth day of life. Supraventricular tachycardia, a cardiac emergency, is characterised by a heart rate between 200 and 300 beats per minute (bpm), often ≥220 bpm. We present the case of a 2-week-old moderately preterm male neonate whose heart rate was found to be persistently above 220 bpm (250–260 bpm) during the second week of life. There was no preceding fever or other clinically significant antecedent. Investigation findings were essentially normal except for the initial limited echocardiogram, which showed sinus venous venosus atrial septal defect. Ice packs were initially applied to the face for vagal stimulation, but there was no satisfactory response. Intravenous adenosine was subsequently administered, with minimal reduction in the heart rate, which remained between 185 and 200 bpm. Oral propranolol was thereafter commenced as a maintenance regimen. The heart rate plateaued between 160 and 170 bpm until the end of the first month of life. The child was discharged home at the beginning of the fifth week of life. He was reviewed at specific intervals in the neonatology outpatient department after hospital discharge. Tapering of propranolol was commenced when the child was 4 months old, and the medication was finally discontinued after the sixth outpatient clinic visit, when the child was 6 months old. The heart rate had stabilised between 120 and 140 bpm. Repeat surface electrocardiographic (ECG) findings at 6 months of life showed normal sinus rhythm, while repeat definitive echocardiograms at 3 and 6 months of life showed normal structural intracardiac and functional findings.