Related Experiment Videos
The effect of phase separation on biphasic waveform defibrillation
R A Cooper1, S T Wallenius, W M Smith
1Department of Medicine, Duke University Medical Center, Durham, North Carolina 27710.
Pacing and Clinical Electrophysiology : PACE
|March 1, 1993
Summary
Separating biphasic shock phases up to 6 msec did not change defibrillation efficacy. Longer delays increased defibrillation thresholds, suggesting rapid voltage change isn't key to biphasic waveform effectiveness.
Area of Science:
- Cardiovascular Research
- Biomedical Engineering
- Electrophysiology
Background:
- Biphasic shocks are effective for defibrillation.
- The rapid voltage change at phase reversal is hypothesized to cause this efficacy.
Purpose of the Study:
- To investigate the effect of interphase delay on biphasic waveform defibrillation efficacy.
- To determine if splitting the rapid voltage change impacts defibrillation thresholds (DFTs).
Main Methods:
- Three parts of the study used six dogs each.
- Tested biphasic waveforms with varying interphase delays (0-100 msec).
- Used transvenous RV apex cathode and cutaneous chest wall anode electrodes.
Main Results:
- No significant difference in DFTs for phase separations up to 6 msec (Part I) and 5 msec (Part II).
- DFTs significantly increased for delays of 8 and 10 msec (Part I).
- Part III showed increased DFTs for delays of 5-50 msec, decreasing at 100 msec.
Conclusions:
- Defibrillation efficacy remains unchanged with interphase delays up to 6 msec.
- The rapid voltage change during phase reversal does not solely explain biphasic waveform efficacy.
- Interphase delay significantly impacts defibrillation energy requirements at longer durations.