Asymptomatic Idiopathic Belhassen Ventricular Tachycardia in a Neonate Detected Using 'Smart Sock' Wearable Smartphone-Enabled Cardiac Monitoring

Abstract

BACKGROUND Wearable smartphone-enabled cardiac monitoring devices can aid the diagnosis of asymptomatic tachycardia in neonates and infants. This report is of a rare case of left posterior fascicular ventricular tachycardia of Belhassen type detected in a neonate by 'smart sock' cardiac monitoring. CASE REPORT A premature baby boy at 37 weeks gestational age was discharged home after three days without complication, and was given 'smart socks' to wear. He was followed up daily for the management of hyperbilirubinemia, which was treated in the outpatient clinic with a phototherapy blanket. He was admitted to the emergency room (ER) at 6 days of age because his 'smart socks' identified a tachycardia of between 180-200 bpm. His parents reported no fever, cough, nasal congestion, or emesis. On examination in the ER, he was alert with no distress. An electrocardiogram (ECG) showed a sustained monomorphic and wide QRS tachycardia with a heart rate of 200 bpm, right bundle branch block (RBBB), and a superior axis that was compatible with a diagnosis of left posterior fascicular ventricular tachycardia of Belhassen type. The echocardiogram showed a structurally normal heart with normal cardiac function. His tachycardia spontaneously converted to normal sinus rhythm after four hours. He was discharged home three days later without further episodes of tachycardia. Cardiac monitoring using 'smart socks' continued at home, and no further arrhythmias were detected at one year of age. CONCLUSIONS The home use of smartphone-enabled technology to monitor the neonatal and infant cardiac heart rate can identify asymptomatic arrhythmias.

Figure 1.

A rare case of left posterior fascicular ventricular tachycardia of Belhassen type detected in a neonate by ‘smart sock’ cardiac monitoring. The Owlet^® ‘smart sock’ is shown on the left foot of the neonate (A). It is connected to the base station using Bluetooth technology to track the heart rate (without the use of an ECG), and oxygen levels are measured using pulse oximetry technology (B). A camera can be added to provide additional video and audio monitoring. The information is sent to the smartphone with an App in real-time through the base station (B).

Figure 2.

A rare case of left posterior fascicular ventricular tachycardia of Belhassen type detected in a neonate by ‘smart sock’ cardiac monitoring. (A) The electrocardiogram (ECG) on arrival in the emergency room (ER) shows a wide QRS tachycardia, a heart rate of 200 bpm, a QRS interval of 0.11 seconds with right bundle branch block (RBBB). The QRS axis is 255 (superior axis), the QTc is 0.438, and there is no discernible P-wave. (B) The ECG following spontaneous cardio-version version shows normal sinus rhythm, a heart rate of 137 bpm, PR interval 0.14 sec, a QRS interval of 0.07 seconds, a QRS axis of 130, and the QTc is 0.489 (a prolonged QTc).