Document Detail

Prospective comparison of biphasic and monophasic shocks for implantable cardioverter-defibrillators using endocardial leads.
MedLine Citation:
PMID:  1632393     Owner:  NLM     Status:  MEDLINE    
Bidirectional shocks using 2 current pathways have been used in endocardial lead systems for implantable cardioverter-defibrillators, but the optimal shock waveform for endocardial defibrillation is unknown. The clinical efficacy and electrical characteristics of bidirectional monophasic and biphasic shocks for endocardial cardioversion-defibrillation of fast monomorphic or polymorphic ventricular tachycardia (VT), or ventricular fibrillation (VF) were evaluated. Thirty-three patients (mean age 60 +/- 12 years, and mean left ventricular ejection fraction 34 +/- 13%) were studied. Defibrillation catheter electrodes were located in the right ventricular apex and superior vena cava/right atrial junction. A triple-electrode configuration including the 2 catheter electrodes and a left thoracic patch was used to deliver bidirectional shocks from the right ventricular cathode to an atrial anode (pathway 1) and the thoracic patch (pathway 2). The shock waveforms examined were sequential and simultaneous monophasic, and simultaneous biphasic. The efficacy of 580 V (20 J) shocks for fast monomorphic VT were comparable for the 3 waveforms (73% for sequential monophasic, 73% for simultaneous monophasic, and 100% for simultaneous biphasic). However, for polymorphic VT and VF, 580 V sequential monophasic shocks had a significantly lower efficacy (25%) than did simultaneous monophasic (75%; p = 0.01) or biphasic (89%; p less than 0.001) shocks. Single-shock defibrillation thresholds with simultaneous biphasic shocks were significantly lower (9 +/- 5 J) than were those with simultaneous monophasic shocks (15 +/- 4 J; p less than 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)
S Saksena; H An; R Mehra; P DeGroot; R B Krol; E Burkhardt; D Mehta; T John
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Publication Detail:
Type:  Clinical Trial; Comparative Study; Controlled Clinical Trial; Journal Article    
Journal Detail:
Title:  The American journal of cardiology     Volume:  70     ISSN:  0002-9149     ISO Abbreviation:  Am. J. Cardiol.     Publication Date:  1992 Aug 
Date Detail:
Created Date:  1992-08-20     Completed Date:  1992-08-20     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0207277     Medline TA:  Am J Cardiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  304-10     Citation Subset:  AIM; IM    
Division of Cardiology, University of Medicine and Dentistry of New Jersey-New Jersey Medical School, Newark.
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MeSH Terms
Electric Countershock / instrumentation,  methods*
Middle Aged
Prospective Studies
Prostheses and Implants*
Tachycardia / therapy
Ventricular Fibrillation / therapy

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