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Ventricular defibrillation with triphasic waveforms.

J Huang1, B H KenKnight, D L Rollins

  • 1Cardiac Rhythm Management Laboratory, Division of Cardiovascular Diseases, Department of Medicine, Department of Physiology, and Department of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, AL, USA.

Circulation
|March 22, 2000
PubMed
Summary
This summary is machine-generated.

Triphasic defibrillation waveforms may be more efficient than biphasic ones, especially with an 80% tilt and specific electrode polarity. However, their superiority is not consistent across all configurations and capacitor sizes.

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Area of Science:

  • Cardiovascular Research
  • Biomedical Engineering
  • Electrophysiology

Background:

  • Triphasic waveforms are hypothesized to cause less myocardial injury than biphasic waveforms.
  • This study investigates the defibrillation thresholds (DFTs) of triphasic versus biphasic waveforms.

Purpose of the Study:

  • To compare the defibrillation efficacy of triphasic and biphasic waveforms.
  • To evaluate the impact of waveform tilt, phase durations, and electrode polarity on DFTs.

Main Methods:

  • Defibrillation thresholds were determined in pigs using transvenous lead systems.
  • Both triphasic and biphasic waveforms were tested with varying capacitor sizes (300-microF and 140-microF) and tilts.
  • The effect of electrode polarity (anodal vs. cathodal) on DFT was assessed for each waveform.

Main Results:

  • Triphasic waveforms with an 80% tilt and specific electrode polarity demonstrated significantly lower DFTs compared to biphasic waveforms using a 300-microF capacitor.
  • In another group, triphasic waveforms with 49% and 56% tilt showed lower energy requirements than biphasic waveforms with similar tilts, but only for anodal phase 1.
  • Electrode polarity significantly influenced the DFT for triphasic waveforms in both experimental groups.

Conclusions:

  • Certain triphasic waveforms (e.g., 80% tilt) can defibrillate more efficiently than biphasic waveforms with a 300-microF capacitor.
  • Triphasic waveforms were not found to be superior to biphasic waveforms from a 140-microF capacitor.
  • The effectiveness of triphasic defibrillation is contingent upon specific phase durations and electrode polarity.