Document Detail

Biphasic and monophasic shocks for transthoracic defibrillation: a meta analysis of randomised controlled trials.
MedLine Citation:
PMID:  12867304     Owner:  NLM     Status:  MEDLINE    
INTRODUCTION: Biphasic waveforms are routinely used for implantable defibrillators. These waveforms have been less readily adopted for external defibrillation. This study was performed in order to evaluate the efficacy and harms of biphasic waveforms over monophasic waveforms for the transthoracic defibrillation of patients in ventricular fibrillation (VF) or haemodynamically unstable ventricular tachycardia. METHODS: Studies included randomised controlled trials comparing monophasic and biphasic external defibrillation for participants with VF or hemodynamically unstable ventricular tachycardia. Seven trials (1129 patients) were included in the analysis. All trials were conducted during electrophysiology procedures or implantable cardioverter/defibrillator testing. RESULTS: Compared with 200 J monophasic shocks, 200 J biphasic shocks reduced the risk of post-first shock asystole or persistent VF by 81% (relative risk (RR) 0.19; 95% confidence intervals (CI) 0.06-0.60) for the first shock. Reducing the energy of the biphasic waveform to 115-130 J resulted in similar effectiveness compared with the monophasic waveform at 200 J (RR 1.07, CI 0.66-1.74). Low energy biphasic shocks produce less myocardial injury than higher energy monophasic shocks as determined by ST segment deflection after shock. CONCLUSIONS: Biphasic waveforms defibrillate with similar efficacy at lower energies than standard 200 J monophasic waveforms, and greater efficacy than monophasic shocks of the same energy. Available data suggests that lower delivered energy and voltage result in less post-shock myocardial injury.
Steven C Faddy; Jane Powell; Jonathan C Craig
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Publication Detail:
Type:  Journal Article; Meta-Analysis    
Journal Detail:
Title:  Resuscitation     Volume:  58     ISSN:  0300-9572     ISO Abbreviation:  Resuscitation     Publication Date:  2003 Jul 
Date Detail:
Created Date:  2003-07-17     Completed Date:  2003-12-11     Revised Date:  2009-08-25    
Medline Journal Info:
Nlm Unique ID:  0332173     Medline TA:  Resuscitation     Country:  Ireland    
Other Details:
Languages:  eng     Pagination:  9-16     Citation Subset:  IM    
Cardiology Department, St Vincent's Hospital Sydney, Victoria St, Darlinghurst, NSW 2010, Australia.
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MeSH Terms
Defibrillators, Implantable
Electric Countershock / methods*
Randomized Controlled Trials as Topic
Tachycardia, Ventricular / therapy

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