Document Detail

Combined effect of beating rate and hydrostatic pressure on excitation in cardiac muscle.
MedLine Citation:
PMID:  7135634     Owner:  NLM     Status:  MEDLINE    
Canine cardiac Purkinje fibers stimulated at frequencies from 1-4 Hz were exposed to hydrostatic pressures of 1 and 150 ATA. Both increases in stimulation frequency and pressure slowed conduction and decreased maximum upstroke velocity of the action potential. Depression of these variables was greatest when rapid rate and elevated pressure were combined. Membrane potential decreased at 150 ATA at all frequencies. Post-overdrive hyperpolarization was reduced 45% at 150 ATA. Action potential duration increased at 150 ATA at all frequencies. Elevated pressure had no effect on the interval dependence of repolarization time to -60 mV but had a slight effect on time to full repolarization. Pressure effect on resting potential was reduced in elevated extracellular potassium. Arrhythmias developed in more than 50% of the tissues at 150 ATA and a frequency of 4 Hz. The results are discussed with respect to ionic mechanisms underlying action potential propagation, to electrogenic pump activity, and to the arrhythmogenic nature of pressure-frequency interactions.
T J Doubt; P M Hogan
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Publication Detail:
Type:  Comparative Study; In Vitro; Journal Article    
Journal Detail:
Title:  Undersea biomedical research     Volume:  9     ISSN:  0093-5387     ISO Abbreviation:  Undersea Biomed Res     Publication Date:  1982 Sep 
Date Detail:
Created Date:  1982-12-21     Completed Date:  1982-12-21     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  0421514     Medline TA:  Undersea Biomed Res     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  241-53     Citation Subset:  IM; S    
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MeSH Terms
Action Potentials
Arrhythmias, Cardiac / etiology
Heart / physiology*
Heart Rate*
Hydrostatic Pressure*
Membrane Potentials
Purkinje Fibers / physiology

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

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