Document Detail


Dependence of anisotropic myocardial electrical resistivity on cardiac phase and excitation frequency.
MedLine Citation:
PMID:  7702534     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Knowledge of myocardial electrical resistivity is of interest because passive electrical properties govern the electrotonic spread of current through the myocardium and influence the shape and velocity of the excitation wave. In addition, measurements of myocardial resistivity may provide information about tissue structure and components. The aim of the present study was to determine the excitation frequency dependence and the changes during the cardiac cycle of anisotropic myocardial electrical resistivity. Longitudinal and transverse myocardial resistivity were measured using an epicardial sensor in four open-chest dogs with excitation frequencies in the range of 5-60 kHz. Mean longitudinal resistivity gradually decreased from 313 +/- 49 omega.cm at 5 kHz to 212 +/- 32 omega.cm at 60 kHz, transverse resistivity decreased from 487 +/- 49 to 378 +/- 53 omega.cm. To analyze the phasic changes, we compared mean resistivity (averaged over the full cardiac cycle) with resistivity during four cardiac phases: pre-ejection, ejection, early diastole and late diastole. Longitudinal resistivity was significantly higher during the ejection phase (+9.6 +/- 4.1 omega.cm) and lower during late diastole (-6.9 +/- 2.9 omega.cm). Transverse resistivity was significantly higher during late diastole (+4.0 +/- 2.3 omega.m). The values during the other cardiac phases were not significantly different from mean resistivity. The phasic changes in longitudinal and transverse resistivity during the cardiac cycle were independent of the excitation frequency. We speculate that these changes are related to geometrical changes, especially to changes in myocardial blood volume.
Authors:
P Steendijk; E T van der Velde; J Baan
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Basic research in cardiology     Volume:  89     ISSN:  0300-8428     ISO Abbreviation:  Basic Res. Cardiol.     Publication Date:    1994 Sep-Oct
Date Detail:
Created Date:  1995-04-28     Completed Date:  1995-04-28     Revised Date:  2003-11-14    
Medline Journal Info:
Nlm Unique ID:  0360342     Medline TA:  Basic Res Cardiol     Country:  GERMANY    
Other Details:
Languages:  eng     Pagination:  411-26     Citation Subset:  IM    
Affiliation:
Leiden University Hospital, Department of Cardiology, The Netherlands.
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MeSH Terms
Descriptor/Qualifier:
Animals
Anisotropy
Dogs
Electric Conductivity
Electrophysiology
Heart / physiology*

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


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