Background Whereas SVTs are well recognised in neonates with early diagnosis and management occasionally ectopic atrial tachycardia in neonates do happen infrequently and could be mis diagnosed as sinus tachycardia particularly if in the slower range

Objectives The tachycardia in these instances often tend to be incessant and can lead to tachycardia induced cardiomyopathy if the rate remains uncontrolled. The ECG changes are subtle and needs a trained eye to pick up this diagnosis.

Methods We present a case of a male infant who presented acutely to the hospital at age of 19 days with blood in the stool. He was born at term baby with mild intra uterine growth retardation but otherwise well at birth. He was noted to have hypospadias and was diagnosed as a case of cow’s milk protein intolerance. During the admission he was incidentally noted to be tachycardic with a heart rate consistently between 180 and 200 beats per minute while otherwise being well and afebrile. His ECG showed narrow complex tachycardia at a rate between 180 to 200 beats per minute. Blood tests were overall satisfactory with an elevated troponin level and negative viral serology studies. An echocardiography done suggested mild left atrial and left ventricular dilatation with mild impairment of function. The case was discussed with the tertiary Cardiac team who felt this was more likely to be a sinus tachycardia and the patient was subsequently discharged. At age of 6 weeks, the child was seen in the outreach cardiac clinic. The ECGs (Current and previous were reviewed). It was noted that P waves were normal axis but negative in aVL, the PR interval was disproportionately long for the tachycardia. This suggested atrial tachycardia which was persistent. An echocardiogram showed a structurally normal heart with mild left heart volume overload and mildly impaired left ventricular function. The child was stuck in a slow atrial tachycardia rhythm which contributed towards the impaired function. Propranolol was started at a dose of 1 mg/kg TDS.

Results At further follow up at 7 months, the child was thriving and well, echocardiography showed that the cardiac dimensions were normal and the function had improved. ECGs and ambulatory monitoring showed normal rates and rhythms. The beta blockers were continued with a plan to wean in future.

Conclusions Ectopic atrial tachycardia (EAT) in a neonate can present with incessant tachycardia but can be in a slower range of 180–200 bpms. The ECG changes can be subtle with normal p waves (P wave axis could be abnormal) but the persistent tachycardia, disproportionately long PR interval for the tachycardia and impairment of ventricular function could be useful pointers towards this diagnosis. EAT could lead to impairment of ventricular function if poorly controlled. Medications to control the tachycardia can help with eventual recovery of ventricular function as this case has highlighted.