| Effects of acute ischemia on anisotropic conduction in canine ventricular muscle. | |
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MedLine Citation:
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PMID: 7690934 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The effects of acute ischemia on conduction velocities in the longitudinal (theta L) and transverse (theta T) fiber axis were determined from epicardial activation patterns, recorded with 48 bipolar electrodes (plaque electrode, 25 x 35 mm) on the left anterior ventricular wall of eight dogs and the posterior wall of seven dogs. During left ventricular stimulation (cycle length = 300 msec) in the center of the plaque electrode, theta L, theta T, and the ratio of longitudinal to transverse conduction velocities (theta L/T) were measured before and 2 to 5 minutes after occlusion of the left anterior descending coronary artery or the left circumflex coronary artery. During the control state theta L was greater than theta T demonstrating anisotropic properties of cardiac muscle, not only in the anterior but also in the posterior wall. During acute ischemia theta L and theta T were decreased from the control value and theta T was decreased by a greater extent than theta L resulting in an increase in theta L/T from 1.83 +/- 0.31 (mean +/- SD) to 2.19 +/- 0.36 in the anterior wall and from 1.58 +/- 0.17 to 1.92 +/- 0.28 in the posterior wall. During ventricular fibrillation some lines of conduction block were parallel to the long axis of epicardial muscle fiber bundle and the others were perpendicular. In conclusion, acute ischemia increased anisotropic conduction (theta L/T) in the epicardial ventricular muscle mainly due to greater reduction in theta T, in the anterior and the posterior wall. This augmented anisotropic ventricular conduction may have some relation to the initiation of ventricular fibrillation during acute ischemia. |
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Authors:
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K Mizumaki; A Fujiki; M Tani; T Misaki |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Pacing and clinical electrophysiology : PACE Volume: 16 ISSN: 0147-8389 ISO Abbreviation: Pacing Clin Electrophysiol Publication Date: 1993 Aug |
Date Detail:
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Created Date: 1993-10-21 Completed Date: 1993-10-21 Revised Date: 2007-11-15 |
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: 1656-63 Citation Subset: IM |
Affiliation:
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Second Department of Internal Medicine, Toyama Medical & Pharmaceutical University, Japan. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Animals Arrhythmias, Cardiac / physiopathology Dogs Electric Stimulation / instrumentation Electrocardiography Electrodes Heart Block / physiopathology Heart Conduction System / physiopathology* Heart Ventricles / innervation, pathology, physiopathology Myocardial Ischemia / physiopathology* Neural Conduction / physiology Pericardium / innervation, physiopathology Ventricular Fibrillation / physiopathology Ventricular Function, Left / physiology* |
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