A single low-energy biphasic shock delivered by a wearable cardioverter defibrillator reliably terminated electrically induced ventricular fibrillation in 100% of episodes.
Does a Wearable Cardioverter Defibrillator (WCD) using biphasic shocks reliably terminate electrically induced ventricular fibrillation in patients undergoing electrophysiological testing?
A single low-energy biphasic shock (70 J or 100 J) delivered by a wearable cardioverter defibrillator reliably terminates electrically induced ventricular fibrillation in 100% of tested episodes.
The Wearable Cardioverter Defibrillator (WCD) automatically detects and treats ventricular tachyarrhythmias without the need for assistance from a bystander, while at the same time allowing the patient to ambulate freely. It represents an alternative to emergency medical services for outpatient populations with a temporary risk of sudden cardiac death. While the original devices used a monophasic truncated exponential waveform for cardioversion/defibrillation shocks, a new, biphasic shock was developed for the next device generation. In 12 patients undergoing electrophysiological testing for ventricular tachyarrhythmias, termination of electrically induced ventricular fibrillation (VF) was attempted via the WCD. In 22 episodes, induced VF was promptly terminated by the first 70 J (n=12) or 100 J (n=10) biphasic shocks. Time between arrhythmia initiation and shock delivery was 22 +/- 6 seconds (70 J) and 21 +/- 6 seconds (100 J) (P=NS). The measured transthoracic impedance was 71 +/- 5 Ohms (64-79 Ohms) for the 70 J shock and 64 +/- 8 Ohms (47-72 Ohms) for the 100 J shock. The present study demonstrates that a single low energy biphasic shock delivered by the WCD, reliably terminates electrically induced VF (100% of episodes). The results of this study suggest that there is an acceptable safety margin to the maximum output of the device (150 J). Despite our promising data, we recommend that programming all shocks for maximum energy output should be done when using the WCD in ambulatory patients.
Reek et al. (Wed,) conducted a other in Ventricular tachyarrhythmias (n=12). Wearable Cardioverter Defibrillator (WCD) using biphasic shocks was evaluated on Termination of electrically induced ventricular fibrillation. A single low-energy biphasic shock delivered by a wearable cardioverter defibrillator reliably terminated electrically induced ventricular fibrillation in 100% of episodes.
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