| Postshock recovery interval of relatively refractory myocardium as a possible explanation for disparate defibrillation efficacy between monophasic and biphasic waveforms. | |
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MedLine Citation:
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PMID: 9633067 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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We investigated the electrophysiological background for the waveform related variability of defibrillation efficacy. In 22 open-chest dogs, a localized potential gradient was created using an 8-V or 16-V field stimulus across a pair of plate electrodes separated by 5 mm. The post shock recovery interval of the nondepolarized myocardium adjacent to the excited area was estimated by the residual refractory period after an appropriately timed field stimulus. The postshock recovery interval and the defibrillation threshold were compared among six different waveforms but with the same total duration of 12 ms (n = 11) or 16 ms (n = 11). Six defibrillation thresholds in individual hearts showed a significant inverse correlation with postshock recovery intervals in most dogs (8/11) tested with a total pulse duration of 12 ms (8 V stimulus: r = -0.80 +/- 0.20 [n = 11]). In contrast, waveforms with a total duration of 16 ms failed to reveal this distinct relationship. We conclude that the waveform related variability of defibrillation efficacy is associated with the refractoriness of relatively refractory myocardium when the total pulse duration is within a certain range. However, the mechanisms responsible for waveform performance may vary as the total pulse duration changes. |
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Authors:
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Y Murakawa; T Yamashita; K Sezaki; Y Kanese; M Omata |
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Publication Detail:
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Type: Comparative Study; Journal Article |
Journal Detail:
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Title: Pacing and clinical electrophysiology : PACE Volume: 21 ISSN: 0147-8389 ISO Abbreviation: Pacing Clin Electrophysiol Publication Date: 1998 Jun |
Date Detail:
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Created Date: 1998-08-26 Completed Date: 1998-08-26 Revised Date: 2006-11-15 |
Medline Journal Info:
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Nlm Unique ID: 7803944 Medline TA: Pacing Clin Electrophysiol Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: 1247-53 Citation Subset: IM |
Affiliation:
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Second Department of Internal Medicine, University of Tokyo, Japan. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Animals Dogs Electric Countershock* / methods Electrophysiology Heart / physiopathology* Myocardial Contraction / physiology* Refractory Period, Electrophysiological Time Factors |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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