Linked Life Data

9915631

Source:http://linkedlifedata.com/resource/pubmed/id/9915631

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2-3
pubmed:dateCreated
1999-4-7
pubmed:abstractText
Patients with essential hypertension often show alterations of the autonomic nervous system. We evaluated the sympathetic and parasympathetic drive to the heart in 12 mildly hypertensive patients and 9 healthy subjects by power spectral analysis of heart rate variability. All subjects underwent measurements of RR interval, low (LF) and high frequency (HF) components of heart rate variability, LF/HF ratio and blood pressure in the resting and sitting positions, both before and after oral clonidine (300 microg), a central sympatholytic agent. In the supine position before clonidine, hypertensive patients had higher blood pressure and lower HF values than healthy subjects. Clonidine induced increases in RR interval and HF in both groups, while LF and LF/HF ratio decreased in healthy subjects, but not in hypertensive patients. On assuming the sitting position, both groups showed reductions in RR and HF and increments in LF and LF/HF. In healthy subjects, the response to the postural challenge was unaffected by clonidine. In contrast, hypertensive patients showed no changes in LF and LF/HF ratio, and a significantly lower decrease in HF. These differences were probably due to the existence of two subsets of patients, one exhibiting similar responses to clonidine as healthy subjects, and the other showing no appreciable response to the drug. These results suggest that hypertensive patients have an altered sympatho-vagal balance to the heart, which can be unmasked by clonidine. This phenomenon should be taken into account to achieve a better control of the overall cardiovascular risk of hypertensive patients.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0165-1838
pubmed:author
pubmed:issnType
Print
pubmed:day
11
pubmed:volume
74
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
152-9
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1998
pubmed:articleTitle
Effects of clonidine on power spectral analysis of heart rate variability in mild essential hypertension.
pubmed:affiliation
Istituto di Medicina Interna, University of Florence School of Medicine, Italy.
pubmed:publicationType
Journal Article, Clinical Trial, Research Support, Non-U.S. Gov't