Linked Life Data

2919559

Source:http://linkedlifedata.com/resource/pubmed/id/2919559

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
9
pubmed:dateCreated
1989-3-30
pubmed:abstractText
Reduction of random noise by signal averaging is required to uncover ventricular late potentials (LPs). Noise reduction is dependent upon the ambient noise before the study and the number of signal-averaged QRS complexes. Prior studies have used a fixed number of QRS complexes (e.g., 150 to 200) for performing signal-averaged electrocardiograms (SAECGs). Because of variable background noise levels, it was hypothesized that variable noise levels after processing could interfere with detection of LP. Accordingly, SAECGs were performed for each patient to 2 prespecified noise endpoints (expressed as the standard deviation/square root of number of beats): 1.0 microV, which has been used previously as a minimal residual noise level, and 0.3 microV, a low level that generally can be attained in less than 450 beats. Root mean square-voltage noises in the 40-Hz high pass filtered vector magnitude for these studies were 1.36 +/- 0.57 and 0.58 +/- 0.28 microV, respectively. The relative prevalence of LP was evaluated in 3 groups. Group I was comprised of 26 patients with sustained ventricular tachyarrhythmias, group II included 59 patients after myocardial infarction and group III had 14 normal volunteers. The prevalence of LP was greater in group I (69 vs 46%, p less than 0.001) and group II (34 vs 24%, p less than 0.01) with the 0.3-microV studies. In group III, the prevalence did not change (7 vs 7%, difference not significant). The greater detection of LP was due to improved resolution of the terminal low-amplitude QRS segment. Therefore, using the 0.3 microV level instead of 1.0 microV increased sensitivity of LP without loss of specificity.(ABSTRACT TRUNCATED AT 250 WORDS)
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0002-9149
pubmed:author
pubmed:issnType
Print
pubmed:day
1
pubmed:volume
63
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
556-60
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1989
pubmed:articleTitle
Importance of the endpoint of noise reduction in analysis of the signal-averaged electrocardiogram.
pubmed:affiliation
Department of Medicine, Columbia University College of Physicians and Surgeons, New York, New York 10032.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't