Document Detail

Role of vagal feedback from the lung in hypoxic-induced tachycardia in humans.
MedLine Citation:
PMID:  7615465     Owner:  NLM     Status:  MEDLINE    
We assessed the cardiovascular responses to systemic normocapnic hypoxia in five normal subjects, five double lung transplant patients with lung denervation and intact hearts, and five patients with denervated hearts. Progressive normocapnic hypoxia was induced over 10-15 min and maintained for 2-3 min each at 90, 87, 84, and 80% arterial O2 saturation (SaO2). Normal subjects showed the most pronounced mean increase in heart rate (dHR/dSaO2 = 0.86 +/- 0.13 beat/min per 1% SaO2). Three lung-denervated subjects had normal tachycardiac responses (1.6, 0.9, and 0.69 beats/min per 1%), whereas the other two had distinctly lower responses (0.34 and 0.39 beat/min per 1%). Most of the lung-denervated subjects also showed a significant tachycardia with even mild hypoxia; none showed a bradycardiac response to any level of hypoxia. In the heart-denervated group, hypoxic tachycardia was significantly lower than normal (0.29 +/- 0.13 beat/min per 1%). We conclude that vagal feedback from the lungs is not required for the normal chronotropic response to hypoxia in humans; however, this mechanism may contribute significantly to the marked variability in hypoxic-induced tachycardia found among human subjects. These data in humans contrast with the progressive bradycardiac response to hypoxia reported in vagally denervated (or nonhyperpneic) dogs and cats.
P M Simon; B H Taha; J A Dempsey; J B Skatrud; C Iber
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  78     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  1995 Apr 
Date Detail:
Created Date:  1995-08-18     Completed Date:  1995-08-18     Revised Date:  2013-09-26    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol (1985)     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1522-30     Citation Subset:  IM    
Division of Pulmonary and Critical Care Medicine, Mayo Clinic, Rochester 55905, USA.
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MeSH Terms
Anoxia / complications,  physiopathology*
Heart Rate / physiology*
Lung / innervation*,  physiopathology,  surgery
Lung Transplantation
Middle Aged
Respiratory Function Tests
Tachycardia / etiology,  physiopathology*
Vagus Nerve / physiopathology*
Vagus Nerve Injuries

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

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