Document Detail


Defibrillation efficacy of commercially available biphasic impulses in humans. Importance of negative-phase peak voltage.
MedLine Citation:
PMID:  9107169     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
BACKGROUND: Recent studies have shown that specifically shaped biphasic waveforms can lower energy requirements for ventricular defibrillation. We prospectively compared the defibrillation efficacy of three different biphasic wave shapes incorporated in three commercially available implantable defibrillators. The results led to the development of a second protocol in which the importance of negative-phase peak voltage and duration was investigated. METHODS AND RESULTS: Defibrillation threshold (DFT) testing using different biphasic waveforms was performed randomly on 42 patients undergoing implantation of a cardioverter-defibrillator for ventricular arrhythmias. In 23 patients (group 1), 3 waveforms were tested: a CPI waveform with 60% positive-phase (P1) tilt and 50% negative-phase (P2) tilt, a Medtronic waveform with 65% fixed tilt in both P1 and P2, and a Ventritex waveform with 60% P1 tilt and a P2 leading edge voltage equal to half of the P1 trailing edge voltage. In 19 patients (group 2), 3 biphasic waveforms with equal P1 tilt at 65% but shorter P2 duration or smaller P2 peak voltage were tested. The Endotak C 60 series lead system (CPI) was used in 11 patients in group 1 and 10 patients in group 2. A Transvene lead system (Medtronics) was used in the remaining patients. Stored energy required for defibrillation was significantly lower with the CPI waveform compared with the Ventritex waveform. In group 2, energy requirements were significantly increased for the waveform with a smaller P2 peak voltage, whereas a short P2 duration did not influence defibrillation success. CONCLUSIONS: Our results suggest that specifically shaped biphasic waveforms delivered from commercially available devices can affect energy requirements for defibrillation. More importantly, the amplitude of the P2 peak voltage may be a more critical determinant than the P2 duration for defibrillation success of biphasic waveforms in humans.
Authors:
G Tomassoni; K Newby; S Deshpande; K Axtell; J Sra; M Akhtar; A Natale
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Publication Detail:
Type:  Clinical Trial; Comparative Study; Controlled Clinical Trial; Journal Article    
Journal Detail:
Title:  Circulation     Volume:  95     ISSN:  0009-7322     ISO Abbreviation:  Circulation     Publication Date:  1997 Apr 
Date Detail:
Created Date:  1997-05-13     Completed Date:  1997-05-13     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0147763     Medline TA:  Circulation     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1822-6     Citation Subset:  AIM; IM    
Affiliation:
Electrophysiology Laboratory, Duke University, VA Medical Center, Durham, NC 27705, USA.
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MeSH Terms
Descriptor/Qualifier:
Aged
Defibrillators, Implantable*
Electric Countershock / instrumentation*
Electric Impedance
Equipment Design
Female
Humans
Male
Middle Aged
Prospective Studies
Tachycardia, Ventricular / therapy
Ventricular Fibrillation / therapy

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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