Linked Life Data

7055864

Source:http://linkedlifedata.com/resource/pubmed/id/7055864

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1982-4-20
pubmed:abstractText
To evaluate whether heart-rate-induced changes of the QT interval are dependent on autonomic tone, we studied 13 healthy subjects, mean age 67.5 years. The maximal uncorrected QT from leads I, II, V1 and V6 was determined during atrial pacing at 90 beats/min and 130 beats/min before and after i.v. administration of propranolol, 0.1 mg/kg, and atropine, 0.02 mg/kg. Significant reductions (p less than 0.01) of QT were induced by the paced increases in heart rate before drugs (10%), after propranolol (10%) and after the combination of atropine and propranolol (9%). Propranolol caused no significant change in the QT interval when heart rate was held constant by pacing. In contrast, atropine produced rate-independent reductions of QT interval (5%) in subjects with beta-adrenergic blockade (p less than 0.05). Bazett's formula for heart-rate correction of the QT interval (QTc) was not applicable for atrial overdrive pacing, as it gave proportionately longer QTc values at higher heart rates. These results show that heart rate is a major determinant of the duration of the QT interval and that paced changes in heart rate induce QT-interval responses that are essentially uninfluenced by autonomic tone. The rate-dependent effect of the QT interval produced by elimination of cholinergic tone suggests a direct influence of cholinergic activity on the repolarization of ventricular myocardium.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0009-7322
pubmed:author
pubmed:issnType
Print
pubmed:volume
65
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
435-9
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1982
pubmed:articleTitle
Influence of heart rate and inhibition of autonomic tone on the QT interval.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't