Related Experiment Video
Updated: Oct 1, 2025
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Standardized Model of Ventricular Fibrillation and Advanced Cardiac Life Support in Swine
Published on: January 30, 2020
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Reduced motion external defibrillation: Reduced subject motion with equivalent defibrillation efficiency validated in
Ehud J Schmidt1, Hassan Elahi1, Eric S Meyer1
1Department of Medicine (Cardiology), Johns Hopkins University, Baltimore, Maryland.
Heart Rhythm
|March 3, 2022
Summary
A novel reduced motion external defibrillator (RMD) significantly decreases subject motion during defibrillation by using a tetanizing waveform prior to the biphasic pulse. This method maintains defibrillation effectiveness while reducing pain-related nerve activation.
Area of Science:
- Biomedical Engineering
- Cardiovascular Research
- Medical Devices
Background:
- External defibrillators deliver biphasic pulses for cardiac arrest and arrhythmia cardioversion.
- Short-duration pulses cause intense chest-wall motion due to muscle contraction.
- A reduced motion external defibrillator (RMD) integrates a tetanizing waveform generator to mitigate this motion.
Purpose of the Study:
- To evaluate RMD defibrillation in swine for reduced subject motion and maintained defibrillation effectiveness.
- To assess the potential of RMD to shorten arrhythmia ablation therapy or simplify cardioversion.
Main Methods:
- A tetanizing unit delivered a low-amplitude, long-duration waveform before conventional biphasic defibrillator pulses.
- Forward limb motion was quantified by peak acceleration and limb work in swine.
- Defibrillation thresholds (DFTs) were determined for both RMD and biphasic pulse-only methods.
Main Results:
- Optimal RMD parameters reduced peak accelerations by 74% and limb work by 85% compared to biphasic pulse-only.
- Two distinct acceleration peaks indicated activation of rapid and slower nociceptive nerve fibers.
- Defibrillation thresholds were identical between RMD and biphasic pulse-only defibrillations.
Conclusions:
- RMD defibrillation significantly reduces subject motion compared to conventional methods.
- The RMD approach maintains rhythm restoration efficiency during defibrillation.
- This technology offers a promising method for less traumatic cardioversion and defibrillation procedures.
