| Beat-by-beat modulation of AV conduction. II. Autonomic neural mechanisms. | |
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MedLine Citation:
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PMID: 3789166 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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We examined the mechanism by which autonomic neural activity associated with respiration and blood pressure modulates atrioventricular (AV) conduction in conscious dogs. Mongrel dogs were anesthetized and instrumented under sterile conditions to record atrial and ventricular electrograms and blood pressure. In the conscious state, electrocardiogram (ECG), respiration, blood pressure, and electrograms were recorded continuously, and heart rate and AV interval were plotted graphically as a function of time. To delineate the role(s) of sympathetic and parasympathetic activity, AV conduction was studied during abrupt and linear changes in heart rate after administration of atropine, propranolol, or both. In the basal state and after propranolol, AV interval oscillated with respiration both in the absence of atrial pacing and at pacing rates 10-100 beats/min above control. Following atropine, oscillations in AV interval associated with respiration were abolished; however, linear and abrupt heart rate increases resulted in AV conduction changes that were associated with fluctuations in blood pressure. In contrast, after both atropine and propranolol, alterations in blood pressure or respiration did not influence AV conduction and rate-dependent prolongation of AV conduction occurred. We conclude that in the basal state, AV conduction is influenced predominately by changes in parasympathetic activity which is the major determinant of respiratory-related AV interval oscillations; after atropine, sympathetic activity produces fluctuations in both AV conduction and blood pressure; and intrinsic rate-dependent properties of the AV node are modulated continually by both divisions of the autonomic nervous system. |
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Authors:
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M R Warner; J M deTarnowsky; C C Whitson; J M Loeb |
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Publication Detail:
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Type: Journal Article; Research Support, U.S. Gov't, Non-P.H.S.; Research Support, U.S. Gov't, P.H.S. |
Journal Detail:
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Title: The American journal of physiology Volume: 251 ISSN: 0002-9513 ISO Abbreviation: Am. J. Physiol. Publication Date: 1986 Dec |
Date Detail:
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Created Date: 1987-01-22 Completed Date: 1987-01-22 Revised Date: 2007-11-14 |
Medline Journal Info:
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Nlm Unique ID: 0370511 Medline TA: Am J Physiol Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: H1134-42 Citation Subset: IM |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Animals Atrioventricular Node / physiology* Atropine / pharmacology Autonomic Nervous System / physiology* Blood Pressure Dogs Heart Conduction System / physiology* Heart Rate / drug effects Kinetics Propranolol / pharmacology Respiration |
| Grant Support | |
ID/Acronym/Agency:
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R01-HL-29000/HL/NHLBI NIH HHS |
| Chemical | |
Reg. No./Substance:
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51-55-8/Atropine; 525-66-6/Propranolol |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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