Linked Life Data

16442407

Source:http://linkedlifedata.com/resource/pubmed/id/16442407

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2006-1-30
pubmed:abstractText
Patients with advanced cardiomyopathy develop prolongations in ventricular myocyte action potential duration that are reflected by prolongations of QT intervals on surface electrocardiograms. Recent studies demonstrate that the placement of a left ventricular (LV) assist device, which induces profound cardiac decompression, acutely increases QT intervals within hours. The goal of this study was to use head-up tilt (HUT) to examine electrocardiographic responses to cardiac unloading in patients with cardiomyopathy. Surface electrocardiograms were analyzed during HUT in 21 patients with cardiomyopathy (ejection fraction <30%) and in 33 age-matched controls. Four to 6 different QT and RR intervals were measured at baseline (supine), at 5 and 25 minutes after HUT. The heart-rate-adjusted QT interval (QTc) was calculated using Bazett's formula. The mean QTc in control patients decreased at 5 minutes (426 +/- 31 vs 418 +/- 28 ms, p < 0.05, vs supine) and was unchanged at 25 minutes (426 +/- 31 vs 423 +/- 25 ms, p = NS, vs supine). However, in patients with cardiomyopathy, there was a significant increase in QTc during HUT (455 +/- 45 vs 473 +/- 42 and 479 +/- 42 ms, p < 0.001, vs supine). The change in heart rate during HUT did not differ between patients with cardiomyopathy and controls. In conclusion, HUT is associated with the immediate prolongation of myocardial repolarization in patients with cardiomyopathy. This response was not seen in age-matched controls. These results suggest that adaptations to chronic cardiac distention may include processes that help accelerate repolarization. Conversely, the prolongation of repolarization after unloading may modulate myocardial relaxation and arrhythmogenic risk.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0002-9149
pubmed:author
pubmed:issnType
Print
pubmed:day
1
pubmed:volume
97
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
412-5
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
2006
pubmed:articleTitle
Effect of acute unloading via head-up tilt on QTc prolongation in patients with ischemic or non-ischemic cardiomyopathy.
pubmed:affiliation
Cardiovascular Research Center, Temple University School of Medicine, Philadelphia, Pennsylvania, USA.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't, Research Support, N.I.H., Extramural