Document Detail


Parasympathetic airway response and heart rate variability before and at the end of methacholine challenge.
MedLine Citation:
PMID:  15653958     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
BACKGROUND: The autonomic nervous system plays a primary role in regulating airway caliber, and its dysfunction is likely to contribute to the pathogenesis of airways diseases. Moreover, some findings support the hypothesis that autonomic dysfunction and/or dysregulation contributes to the pathogenesis of airway hyperresponsiveness (AHR). Heart rate variability (HRV) spectral analysis allows identifying noninvasively perturbations of the autonomic system. PURPOSES: We tested the relationship between AHR and cardiac parasympathetic tone assessed by HRV spectral analysis in patients submitted to a diagnostic methacholine bronchial challenge (MBC). METHODS: Fifteen women and 38 men (age range, 18 to 56 years) participated in the study. The principal indications for MBC were suspected asthma, chronic cough, unexplained exercise-induced dyspnea, or cough. The R-R intervals were continuously recorded during the MBC. Autoregressive method was performed on two series of 256 R-R intervals extracted before and after the MBC to obtain low-frequency (LF) and high-frequency (HF) components. RESULTS: The MBC distinguished 29 subjects without airway responsiveness (R-) and 24 responder or hyperresponsive subjects (R+): mean provocative dose of methacholine causing a 20% reduction in mean (+/- SD) FEV1 of 467 +/- 351 microg (range, 70 to 1,426 microg). The HF component expressed in normalized units (n.u.) [the index of parasympathetic modulation] was significantly higher in R+ than in R- at baseline, before MBC (21 +/- 21 n.u. vs 11 +/- 9 n.u., p < 0.05). Interestingly, R+ showed a significant increase of HF component after MBC (243 +/- 30 to 567 +/- 620 ms2 and 21 +/- 21 to 34 +/- 30 n.u., p < 0.01). For all subjects, HF (n.u.) calculated at baseline and after MBC were significantly influenced by the bronchial responsiveness (r2 = -0.28 and -0.51, respectively; p < 0.001). CONCLUSION: In summary, we found that R+ had a significantly higher parasympathetic tone than R- at baseline, and that R+ showed a significant increase in cardiac reactivity after bronchial challenge. These findings demonstrate that the autonomic nervous system, which contributes to the pathogenesis of AHR, is closely linked to cardiac modulation.
Authors:
Aurélien Pichon; Claire de Bisschop; Véronique Diaz; André Denjean
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Chest     Volume:  127     ISSN:  0012-3692     ISO Abbreviation:  Chest     Publication Date:  2005 Jan 
Date Detail:
Created Date:  2005-01-17     Completed Date:  2005-02-22     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0231335     Medline TA:  Chest     Country:  United States    
Other Details:
Languages:  eng     Pagination:  23-9     Citation Subset:  AIM; IM    
Affiliation:
Service d'Explorations Fonctionnelles, Physiologie Respiratoire et de l'Exercice, Pôle Coeur-Poumons, CHU de Poitiers, France. aurelien.pichon@orange.fr
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MeSH Terms
Descriptor/Qualifier:
Adolescent
Adult
Asthma / physiopathology
Bronchial Hyperreactivity / physiopathology*
Bronchial Provocation Tests*
Female
Heart / innervation*
Heart Rate
Humans
Male
Methacholine Chloride / diagnostic use
Middle Aged
Parasympathetic Nervous System / physiology*
Parasympathomimetics / diagnostic use
Chemical
Reg. No./Substance:
0/Parasympathomimetics; 62-51-1/Methacholine Chloride

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


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