Document Detail


Stretch-induced regional mechanoelectric dispersion and arrhythmia in the right ventricle of anesthetized lambs.
MedLine Citation:
PMID:  14766676     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Regional mechanical and electrophysiological changes accompany most ventricular arrhythmias and, it has been suggested, by mechanoelectric feedback. We hypothesized that an intervention producing regional mechanical dispersion was associated with regional, proarrhythmic electrical dispersion and studied the regional mechanoelectric feedback in the right ventricle (RV) of anesthetized lambs. Ten lambs were deeply anesthetized, and their hearts were exposed. Three tripodal devices, each incorporating three monophasic action potential electrodes and an integrated strain-gauge system, were placed on the RV apex outflow and inflow regions. Measurements were made before, during, and after 10-s pulmonary arterial occlusion. Pulmonary arterial occlusion increased RV pressure and overall regional segment length. Length excursion became out of phase with RV pressure beats immediately after occlusion, and the strain patterns were different in the three regions at the peak of occlusion. The occlusion resulted in different alterations in regional monophasic action potential morphology, including reduction in monophasic action potential amplitude and duration by different amounts and early afterdepolarizations that were unevenly distributed in the monophasic action potential recordings. This was associated with dispersion of repolarization and recovery time. The combination of electromechanical events precipitated a variety of arrhythmias. Acute RV distension is proarrhythmic, possibly through a causal relationship among mechanically induced afterdepolarizations, dispersion (heterogeneity) of mechanical strain, and dispersion of electrical recovery. The relationship among the different wall motions, the dispersion of repolarization, and arrhythmia underscored mechanoelectric feedback as an important part of arrhythmogenesis in pulmonary embolism and commotio cordis.
Authors:
Ruo L Chen; Daniel J Penny; Gottfried Greve; Max J Lab
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  American journal of physiology. Heart and circulatory physiology     Volume:  286     ISSN:  0363-6135     ISO Abbreviation:  Am. J. Physiol. Heart Circ. Physiol.     Publication Date:  2004 Mar 
Date Detail:
Created Date:  2004-02-09     Completed Date:  2004-04-01     Revised Date:  2009-11-19    
Medline Journal Info:
Nlm Unique ID:  100901228     Medline TA:  Am J Physiol Heart Circ Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  H1008-14     Citation Subset:  IM    
Affiliation:
Dept. of Physiology, Block 9, St. Thomas Campus, King's College, Univ. of London, Lambeth Palace Rd., London SE1 7BH, UK. ronnie.chen@kcl.ac.uk
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MeSH Terms
Descriptor/Qualifier:
Action Potentials / physiology*
Anesthesia
Animals
Arrhythmias, Cardiac / etiology,  physiopathology*
Feedback, Physiological / physiology
Heart / physiopathology*
Heart Ventricles / physiopathology
Pulmonary Artery / physiopathology
Pulmonary Embolism / physiopathology
Sheep
Stress, Mechanical

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


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