Document Detail

Dynamic sympathetic control of atrioventricular conduction time and heart period.
MedLine Citation:
PMID:  11247770     Owner:  NLM     Status:  MEDLINE    
Although power spectra of R-R and P-R intervals in response to random respiration show similar frequency distributions, the way in which dynamic sympathetic regulation contributes to such similarity remains unknown. We estimated the transfer function from sympathetic stimulation to the atrioventricular interval (AV conduction time; T(AV)) with and without constant atrial pacing in seven anesthetized cats. The transfer function from sympathetic stimulation to T(AV), except for absolute gain values, approximated a low-pass filter similar to that from sympathetic stimulation to the A-A interval (heart period; T(AA)). The 90%-rise times did not differ between the T(AA) and T(AV) step responses (32.3 +/- 1.8 vs. 29.6 +/- 3.2 s). Constant pacing augmented the T(AV) step response (-0.58 +/- 0.10 vs. -0.86 +/- 0.12 ms/Hz, P < 0.05) without affecting the 90%-rise time. These findings suggest that the dynamic characteristics of sympathetic control are similar between T(AA) and T(AV) despite the different electrophysiological mechanisms determining T(AA) and T(AV). A numerical simulation indicated that if the dynamic characteristics of the sympathetic control do not match between T(AA) and T(AV), a critical condition for initiation of reentrant tachycardia would be encountered.
T Kawada; S L Chen; M Inagaki; T Shishido; T Sato; T Tatewaki; M Sugimachi; K Sunagawa
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
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 Apr 
Date Detail:
Created Date:  2001-03-15     Completed Date:  2001-04-19     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  100901228     Medline TA:  Am J Physiol Heart Circ Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  H1602-7     Citation Subset:  IM    
Department of Cardiovascular Dynamics, National Cardiovascular Center Research Institute, Suita, Osaka 565-8565, Japan.
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MeSH Terms
Atrioventricular Node / innervation*,  physiology*
Bundle of His / physiology
Electric Stimulation
Heart / innervation,  physiology*
Heart Rate
Sympathetic Nervous System / physiology
Time Factors
Vagus Nerve / physiology

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