Document Detail

The high frequency component of heart rate variability reflects cardiac parasympathetic modulation rather than parasympathetic 'tone'.
MedLine Citation:
PMID:  8619324     Owner:  NLM     Status:  MEDLINE    
This study was designed to evaluate the effect of modulating cardiac parasympathetic input on the high frequency component of heart rate variability. We stimulated the right vagus nerve with three different stimulation patterns in anaesthetized, vagotomized and spinal anaesthetized dogs. We kept the mean stimulation frequency constant; controlled the amplitude of modulation with programmed stimulation patterns, and analysed the resulting heart rate variability by power spectral analysis. Constant frequency vagal stimulation increased the cardiac interval, but did not change heart rate variability markedly. There was a slight increase, from 11 +/- 2 to 27 +/- 11 ms2, in the high frequency component. However, when the instantaneous stimulation frequency oscillated between 4 and 17 Hz during 5 s period, we could produce a marked heart rate variation, with 91 +/- 9% of the variation corresponding to the frequency of the modulation (0.20 Hz). The high frequency component was 12932 +/- 7701 ms2. With an increased magnitude of modulation, i.e. the difference between minimum and maximum instantaneous frequency, the high frequency component increased to 32711 +/- 17943 ms2. Thus, the high frequency component of heart rate variability reflects the magnitude of fluctuation in the cardiac parasympathetic input rather than parasympathetic 'tone'.
A E Hedman; J E Hartikainen; K U Tahvanainen; M O Hakumäki
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Acta physiologica Scandinavica     Volume:  155     ISSN:  0001-6772     ISO Abbreviation:  Acta Physiol. Scand.     Publication Date:  1995 Nov 
Date Detail:
Created Date:  1996-06-07     Completed Date:  1996-06-07     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  0370362     Medline TA:  Acta Physiol Scand     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  267-73     Citation Subset:  IM    
Department of Physiology, University of Kuopio, Finland.
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MeSH Terms
Anesthesia, Spinal
Aorta / physiology
Autonomic Denervation
Blood Pressure / physiology
Electric Stimulation
Evaluation Studies as Topic
Heart / innervation*,  physiology
Heart Rate / physiology*
Parasympathetic Fibers, Postganglionic / physiology*
Vagus Nerve / physiology

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