| Marked reduction of ventricular defibrillation threshold by application of an auxiliary shock to a catheter electrode in the left posterior coronary vein of dogs. | |
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MedLine Citation:
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PMID: 10969753 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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INTRODUCTION: For endocardial shocks near the defibrillation threshold (DFT), postshock activity originates from the lateral left ventricular apex, where the shock field is weak. This study tested the hypothesis that an auxiliary shock (AS) delivered between an electrode at this site and a superior vena cava (SVC) electrode before the primary endocardial shock (PS) would reduce the DFT. METHODS AND RESULTS: In six pentobarbital-anesthetized dogs (26 to 36 kg), catheter electrodes were placed in the right ventricular (RV) apex and the SVC. To simulate transvenous introduction, a small electrode was inserted into the posterior cardiac vein using an epicardial approach. For dual shock treatments, AS (2-msec monophasic) was applied to the coronary vein electrode at different time intervals before a biphasic PS (4 msec/3 msec) to the RV-SVC electrodes. The mean DFT energy for dual shocks treatments were significantly reduced (P < 0.05) in comparison to the control treatment (no AS, 26.5+/-8.8 J). Mean DFT energy after 10 seconds of electrically induced ventricular fibrillation for dual shocks, in which AS and PS were separated by 1, 5, 10, and 20 msec, were 10.2+/-4.1 J, 10.9+/-5.5 J, 11.3+/-6.3 J, and 15.4+/-7.2 J, respectively. These values were all significantly lower than the PS alone (26.5+/-8.8 J). CONCLUSION: Addition of an AS from the posterior cardiac vein before an endocardial PS reduces DFT energy by more than 50%. Such DFT reduction could improve therapeutic safety margin or permit reduction in volume of implantable cardioverter defibrillators. |
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Authors:
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B H Kenknight; R G Walker; R E Ideker |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S. |
Journal Detail:
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Title: Journal of cardiovascular electrophysiology Volume: 11 ISSN: 1045-3873 ISO Abbreviation: J. Cardiovasc. Electrophysiol. Publication Date: 2000 Aug |
Date Detail:
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Created Date: 2000-12-11 Completed Date: 2000-12-22 Revised Date: 2007-11-14 |
Medline Journal Info:
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Nlm Unique ID: 9010756 Medline TA: J Cardiovasc Electrophysiol Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: 900-6 Citation Subset: IM |
Affiliation:
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Department of Therapy Research, Cardiac Rhythm Management (CRM) Group Guidant Corporation, St. Paul, Minnesota, USA. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Animals Catheterization Coronary Vessels / physiopathology* Differential Threshold Dogs Electric Countershock* Electric Stimulation Therapy* Electrodes Veins / physiopathology Ventricular Fibrillation / therapy* |
| Grant Support | |
ID/Acronym/Agency:
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HL-42760/HL/NHLBI NIH HHS |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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