Analysis of the defibrillation efficacy for 5-ms waveforms.


Journal Article

INTRODUCTION: Empirical studies have shown that biphasic defibrillation waveforms are more efficacious than monophasic waveforms. However, a more systematic approach to waveform development might be more productive. This study tested 147 multiphasic waveforms uniformly sampled from all possible 5-ms waveforms. METHODS AND RESULTS: One hundred ninety-eight guinea pigs (850-1,050 g) received 30 episodes of ventricular fibrillation followed by transthoracic defibrillation. The first 10 shocks were used to determine the ED(50) for a biphasic control. Then, 20 waveforms including 2 controls were tested once at the ED(50). Of the 147 waveforms tested here, 21 waveforms showed equivalent or greater efficacies than the biphasic control, with one being statistically more efficacious (P < 0.05). Two fundamental assumptions were addressed: (1) similarly efficacious waveforms are analytically similar, and (2) a single optimal waveform can be described. The mean percentage of similarly efficacious waveforms with similar shapes was greater than zero in the most efficacious 21 waveforms (P = 0.023), but less efficacious waveforms showed randomly distributed shapes. Cluster analysis revealed that the best waveforms share a major phase containing most of the defibrillation energy. The optimal waveform shape extrapolated from the sample waveforms was a 2.5/1-ms biphasic-type waveform (highest correlation r = 0.701, P < 0.001). CONCLUSION: This work supports the assumption that efficacious waveforms are similarly shaped and the notion that one single optimum exists.

Full Text

Duke Authors

Cited Authors

  • Guan, D; Malkin, R

Published Date

  • April 2004

Published In

Volume / Issue

  • 15 / 4

Start / End Page

  • 447 - 454

PubMed ID

  • 15089995

Pubmed Central ID

  • 15089995

Electronic International Standard Serial Number (EISSN)

  • 1540-8167

International Standard Serial Number (ISSN)

  • 1045-3873

Digital Object Identifier (DOI)

  • 10.1046/j.1540-8167.2004.03253.x


  • eng