Document Detail


Propranolol blocks ventricular refractory period changes with orthostatic stress in humans.
MedLine Citation:
PMID:  3192847     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The purpose of this study was to test the hypothesis that orthostatic stress shortens the right ventricular effective refractory period by reflex activation of beta-adrenergic receptors. Twelve patients undergoing electrophysiologic testing for standard clinical indications were studied. After a full electrophysiologic study, patients underwent graded lower body negative pressure before and after administration of either propranolol (0.2 mg/kg intravenously) in Group I or atropine (0.035 mg/kg intravenously) in Group II. Before the addition of drugs, lower body negative pressure produced decreases in systolic blood pressure and significant increases in sinus rate. The effective refractory period shortened from 214 +/- 8 (mean +/- SEM) to 206 +/- 7 ms at -40 cm H2O and to 197 +/- 4 ms at -60 cm H2O lower body negative pressure. After propranolol, Group I patients had no change in right ventricular effective refractory period despite similar changes in sinus rate and systolic blood pressure. In group II patients, atropine did not alter effective refractory period responses to lower body negative pressure. Thus, reflex adjustments to orthostatic stress result in shortening of right ventricular effective refractory period mediated by way of beta-adrenergic mechanisms. These findings constitute the first evidence that sympathetic influences mobilized by the body can directly modulate ventricular electrophysiologic changes.
Authors:
J B Martins; M G Kienzle; M L McCue; L Constantin
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Journal of the American College of Cardiology     Volume:  12     ISSN:  0735-1097     ISO Abbreviation:  J. Am. Coll. Cardiol.     Publication Date:  1988 Dec 
Date Detail:
Created Date:  1989-01-06     Completed Date:  1989-01-06     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  8301365     Medline TA:  J Am Coll Cardiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1488-93     Citation Subset:  AIM; IM; S    
Affiliation:
Department of Internal Medicine, University of Iowa, Iowa City.
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MeSH Terms
Descriptor/Qualifier:
Adult
Aged
Atropine / pharmacology
Blood Pressure / drug effects
Decompression*
Female
Heart / drug effects*,  physiology
Heart Rate / drug effects
Humans
Lower Body Negative Pressure*
Male
Middle Aged
Neural Conduction / drug effects*
Propranolol / pharmacology*
Reflex
Refractory Period, Electrophysiological / drug effects*
Grant Support
ID/Acronym/Agency:
HL32295/HL/NHLBI NIH HHS; RR59/RR/NCRR NIH HHS
Chemical
Reg. No./Substance:
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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