Heart Rate Threshold Settings for Ventricular Tachycardia in Patients with Wearable Cardioverter-defibrillators.

The wearable cardioverter-defibrillator (WCD) uses programmable heart rate (HR) and detection time to determine the need for shock delivery, but the optimal ventricular tachycardia (VT) HR detection zone is unknown. The LifeVest™ (ZOLL Medical, Chelmsford, MA, USA) WCD has a default VT detection rate of 150 bpm. We found that 15% of appropriate shocks among WCD recipients were delivered for VT 150-170 bpm and that 30% of these patients experienced loss of consciousness. Based on these findings, a programmed VT detection threshold of 150 bpm should be considered.