Linked Life Data

14617259

Source:http://linkedlifedata.com/resource/pubmed/id/14617259

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
2003-11-17
pubmed:abstractText
Parallel increases or decreases of systolic pressures and R-R intervals occur spontaneously in healthy resting humans, and are thought to be expressions of vagal baroreflex physiology. We studied ten healthy supine young adults, and tested the null hypothesis that spontaneous baroreflex sequences are distributed uniformly throughout the breathing cycle. We recorded the electrocardiogram, photoplethysmographic arterial pressure, respiration (pneumobelt), and peroneal nerve muscle sympathetic activity in supine subjects who breathed spontaneously, or held their breaths in inspiration after 2 min of hyperventilation with 100% oxygen. We analysed pairs of three or more increasing or decreasing systolic pressures and R-R intervals with linear regression, and related the gain and timing of the onset of such sequences to the phase of respiration, and to preceding muscle sympathetic nerve activity. We found that baroreflex sequences occur erratically, at a frequency about one-third that of breathing. However, when baroreflex sequences do occur, the timing of their onset is dictated by the phase of respiration. Parallel increases of systolic pressures and R-R intervals ('up' sequences) begin just before and after the beginning of expiration, and parallel decreases of systolic pressures and R-R intervals ('down' sequences) begin during late expiration and inspiration. Average gains of up and down baroreflex sequences triggered by muscle sympathetic bursts are comparable during breathing and apnoea. However, the latencies between sympathetic bursts and baroreflex sequences are less during breathing than during apnoea. We propose that parallel systolic pressure--R-R interval sequences are expressions of arterial baroreflex physiology, and that the nearly fixed timing of such sequences within breaths reflects simply respiratory gating of muscle sympathetic bursts.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
1475-0961
pubmed:author
pubmed:issnType
Print
pubmed:volume
23
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
307-13
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
2003
pubmed:articleTitle
Spontaneous 'baroreflex sequences' occur as deterministic functions of breathing phase.
pubmed:affiliation
Department of Medicine, Hunter Homes McGuire Department of Veterans Affairs Medical Center and Medical College of Virginia at Virginia Commonwealth University, Richmond, VA 23225, USA.
pubmed:publicationType
Journal Article, Clinical Trial, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S.