Document Detail


Sensitized central controller of ventilation in rats with chronic heart failure contributes to hyperpnea little at rest but more during exercise.
MedLine Citation:
PMID:  17946641     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
BACKGROUND: To understand the pathophysiologic basis of exercise hyperpnea in chronic heart failure (CHF), we have developed an experimental method quantitatively characterizing ventilatory regulation system in rats. An equilibrium diagram illustrates the characteristics of two subsystems, i.e., the central controller (arterial CO2 tension [Pa(CO2)] to minute ventilation [V(E)] relationship) and peripheral plant (V(E) to Pa(CO2) relationship). In this study, we compared these between normal and CHF rats at rest. METHOD: In anesthetized 6 postinfarction CHF rats and 6 normal rats, we induced hypercapnia by changing inspiratory CO2 fraction and measured the steady-state Pa(CO2) to V(E) relation. We altered V(E) by varying the level of artificial ventilation and measured the V(E) to Pa(CO2) relation. RESULTS: Central controller gain S was significantly lager in CHF rats, confirming clinical observation. The V(E) at rest (operating point) in CHF was 24% larger; central hypersensitivity, however, contributed little (6%) to this increase. CONCLUSION: Central hypersensitivity alone would not explain hyperpnea at rest in CHF rats. Considering the right and upward shift of V(E) to Pa(CO2) relation, central hypersensitivity contributes more to hyperpnea during exercise. The potential difference between normal and CHF rats in exercise-induced changes in controller and plant should be examined to fully understand the mechanism of exercise hyperpnea and to develop a method to attenuate this.
Authors:
Tadayoshi Miyamoto; Masashi Inagaki; Hiroshi Takaki; Atsunori Kamiya; Toru Kawada; Toshiaki Shishido; Masaru Sugimachi; Kenji Sunagawa
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference     Volume:  1     ISSN:  1557-170X     ISO Abbreviation:  Conf Proc IEEE Eng Med Biol Soc     Publication Date:  2006  
Date Detail:
Created Date:  2007-10-23     Completed Date:  2008-04-02     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  101243413     Medline TA:  Conf Proc IEEE Eng Med Biol Soc     Country:  United States    
Other Details:
Languages:  eng     Pagination:  4627-30     Citation Subset:  IM    
Affiliation:
National Cardiovascular Center Res. Inst., Suita, Osaka, Japan.
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MeSH Terms
Descriptor/Qualifier:
Animals
Biomedical Engineering / methods
Equipment Design
Exercise*
Exercise Test
Feedback
Heart Failure / diagnosis*,  therapy
Humans
Hyperventilation*
Oxygen Consumption
Pulmonary Ventilation*
Rats
Respiration
Rest

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


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