| Conscious rabbits become tolerant to multiple episodes of ischemic preconditioning. | |
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MedLine Citation:
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PMID: 8156647 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Although ischemic preconditioning protects myocardium from infarction in isolated hearts and in anesthetized open-chest animals, its effects have not been examined in unanesthetized animals. Furthermore, it is unknown whether animals become tolerant to multiple episodes of ischemic preconditioning. Rabbits were chronically instrumented with a balloon occluder around a major branch of the left coronary artery for reversible coronary occlusion, a left atrial catheter for radioactive microsphere injections, ECG electrodes for monitoring of myocardial ischemia, and, in some cases, a carotid artery catheter for pressure measurements and timed withdrawal of reference arterial blood samples. Eight control rabbits underwent a 30-minute coronary occlusion and then 180 minutes of reperfusion. Five of the eight rabbits developed ventricular tachycardia or fibrillation during ischemia, and infarct size averaged 37.7 +/- 2.6% of the risk area. Eight rabbits experienced a 5-minute coronary occlusion and 10 minutes of reperfusion before the 30-minute occlusion. In these preconditioned animals, potentially fatal arrhythmias during ischemia were significantly reduced (one of eight, P < .05), and infarct size was much smaller (5.6 +/- 1.1%, P < .0001). The difference could not be explained by hemodynamics or collateral blood flow, which were nearly identical in the two groups. But when the 30-minute coronary occlusion was preceded by 40 to 65 five-minute occlusions during a 3- to 4-day period in seven animals, protection was markedly attenuated. Potentially lethal arrhythmias were very common, and infarct size averaged 26.5 +/- 2.9%, substantially larger than in rabbits with only one preconditioning occlusion (P < .0001).(ABSTRACT TRUNCATED AT 250 WORDS) |
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Authors:
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M V Cohen; X M Yang; J M Downey |
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Publication Detail:
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Type: Journal Article; Research Support, U.S. Gov't, P.H.S. |
Journal Detail:
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Title: Circulation research Volume: 74 ISSN: 0009-7330 ISO Abbreviation: Circ. Res. Publication Date: 1994 May |
Date Detail:
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Created Date: 1994-05-17 Completed Date: 1994-05-17 Revised Date: 2007-11-14 |
Medline Journal Info:
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Nlm Unique ID: 0047103 Medline TA: Circ Res Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: 998-1004 Citation Subset: IM |
Affiliation:
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Division of Cardiology, University of South Alabama College of Medicine, Mobile 36688. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Animals Collateral Circulation Constriction Heart Rate / physiology Myocardial Infarction / pathology* Myocardial Ischemia / physiopathology* Rabbits Time Factors Ventricular Fibrillation / etiology, physiopathology |
| Grant Support | |
ID/Acronym/Agency:
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HL-17809/HL/NHLBI NIH HHS |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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