Document Detail

Augmentation of respiratory sinus arrhythmia in response to progressive hypercapnia in conscious dogs.
MedLine Citation:
PMID:  11299239     Owner:  NLM     Status:  MEDLINE    
Respiratory sinus arrhythmia (RSA) may serve to enhance pulmonary gas exchange efficiency by matching pulmonary blood flow with lung volume within each respiratory cycle. We examined the hypothesis that RSA is augmented as an active physiological response to hypercapnia. We measured electrocardiograms and arterial blood pressure during progressive hypercapnia in conscious dogs that were prepared with a permanent tracheostomy and an implanted blood pressure telemetry unit. The intensity of RSA was assessed continuously as the amplitude of respiratory fluctuation of heart rate using complex demodulation. In a total of 39 runs of hypercapnia in 3 dogs, RSA increased by 38 and 43% of the control level when minute ventilation reached 10 and 15 l/min, respectively (P < 0.0001 for both), and heart rate and mean arterial pressure showed no significant change. The increases in RSA were significant even after adjustment for the effects of increased tidal volume, respiratory rate, and respiratory fluctuation of arterial blood pressure (P < 0.001). These observations indicate that increased RSA during hypercapnia is not the consequence of altered autonomic balance or respiratory patterns and support the hypothesis that RSA is augmented as an active physiological response to hypercapnia.
F Yasuma; J Hayano
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  American journal of physiology. Heart and circulatory physiology     Volume:  280     ISSN:  0363-6135     ISO Abbreviation:  Am. J. Physiol. Heart Circ. Physiol.     Publication Date:  2001 May 
Date Detail:
Created Date:  2001-04-12     Completed Date:  2001-05-17     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  100901228     Medline TA:  Am J Physiol Heart Circ Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  H2336-41     Citation Subset:  IM    
First Department of Internal Medicine, Nagoya University School of Medicine, Nagoya 466-8550, Japan.
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MeSH Terms
Arrhythmia, Sinus / physiopathology*
Autonomic Nervous System / physiology
Blood Pressure / physiology
Chemoreceptor Cells / physiology
Heart Rate / physiology
Hypercapnia / physiopathology*

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