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Transvenous cardioversion--a novel asymmetric rectangular biphasic waveform from a radiofrequency defibrillator
Journal of Electrocardiology
|January 13, 2004
Summary
A novel radiofrequency (RF) defibrillator safely and effectively converted atrial fibrillation (AF) using asymmetric biphasic waveforms. This device shows promise for future implantable cardioverter-defibrillator applications.
Area of Science:
- Cardiovascular Electrophysiology
- Medical Device Technology
Background:
- Investigated a novel radiofrequency (RF) device for transvenous cardioversion of atrial fibrillation (AF).
- Device utilizes a primary RF transmitter, air gap, and passive secondary unit for direct current waveform generation.
Purpose of the Study:
- To assess the safety and efficacy of a novel RF defibrillator for transvenous cardioversion of AF.
- To compare the performance of rectangular monophasic/biphasic waveforms against conventional tilted waveforms.
Main Methods:
- Device tested in 10 sheep using transvenous leads in the coronary sinus and right atrium.
- Compared novel RF defibrillator with rectangular pulses to conventional tilted waveforms (Ventritex HVS-02).
- Atrial fibrillation induced by rapid pacing; 5 cardioversion attempts per waveform, success defined as sinus rhythm within 5 beats.
Main Results:
- No arrhythmic complications observed across 400 delivered shocks.
- Asymmetric rectangular biphasic waveforms (50% phase 2 voltage) were more efficacious than conventional waveforms.
- Reduced phase 2 voltage did not impact efficacy but facilitated energy reduction.
Conclusions:
- The novel RF defibrillator is safe and effective for transvenous cardioversion of AF.
- Asymmetric rectangular biphasic waveforms offer improved efficacy for AF cardioversion.
- Future design modifications could enable use as an implantable defibrillator with external RF power.