• supraventricular tachycardia
• swallowing

We would like to report on an infant with swallowing induced supraventricular tachycardia (SVT). This has rarely been described in adults,¹ but, to our knowledge, has not been previously reported in neonates or children.

A male infant weighing 4500 g was born by vaginal delivery at term after a normal pregnancy. He was admitted to the neonatal unit for phototherapy and was diagnosed with SVT. There was no haemodynamic instability and he was cardioverted with adenosine. He had recurrent SVT and was started on antiarrhythmic treatment. He subsequently had recurrent SVT which was noted to be precipitated by feeding. SVT did not appear to be triggered by sucking a pacifier but occurred within seconds of feeding. Termination of the SVT usually occurred spontaneously about 30 minutes after the end of a feed. On a few occasions, longer periods of SVT required adenosine for cardioversion. In an attempt to control his SVT, oral feeds were discontinued and he was started on intravenous fluids. He remained in sinus rhythm throughout 18 hours of fasting. When feeding was resumed, he again developed SVT. Treatment with digoxin or propranolol at therapeutic levels did not control the SVT.

There was no evidence of Wolff-Parkinson-White syndrome on the electrocardiogram, which showed a normal cardiac anatomy with good ventricular function. A barium swallow was performed, which revealed a normal oesophageal anatomy and swallowing mechanism. An abdominal ultrasound was normal and showed good diaphragmatic movement with respiration.

Treatment with increasing doses of flecainide resulted in a reduction in the frequency and duration of the SVT. Before discharge on flecainide 3.5 mg/kg/day, a 24 hour continuous ECG recording did not produce any evidence of SVT. This patient subsequently had recurrent SVT unassociated with swallowing and remains on antiarrhythmic treatment.

Swallowing induced SVT has been recognised in adults without evidence of gastro-oesophageal disease² and in association with pharyngoplastic manipulations.³ In one intractable case, intrapleural repositioning of the oesophagus to physically separate it from the right atrium successfully achieved control.⁴ Swallowing increases vagal tone, and thus termination of SVT is often associated with swallowing and other vagal manoeuvres. Changes in vasosympathetic tone or perhaps mechanical stimulation are possible causes for this unusual phenomenon.