Source:http://linkedlifedata.com/resource/pubmed/id/16352227
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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
4
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| pubmed:dateCreated |
2005-12-14
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| pubmed:abstractText |
The frequency of pacing is a fundamental physiological modulator of myocardial function. When the pacing rate increases there is normally an increase in contractility (a positive force-frequency relationship). However in small rodents, fish and end-stage failing myocardium, the force-frequency response has been found to be flat or even negative. The positive staircase is understood to be related with the increase in the intracellular Ca(2+) transient, mainly due to an enhanced sarcoplasmic reticulum Ca(2+) content at higher stimulation frequencies, resulting from an increase in Ca(2+) influx per unit time and reduced Ca(2+) efflux between beats. However, additional mechanisms, such as increased activity of Ca(2+)/calmodulin-dependent protein kinase or enhanced myofilament responsiveness to Ca(2+) may also play a role. Although an increase in contraction frequency has been shown to be associated with an increase in intracellular Na(+), several studies have shown a temporal dissociation between the increase in Na(i)(+) and the increase in force evoked by changes in pacing frequency. The way in which the Na(+)/Ca(2+) exchanger contributes to contraction frequency inotropy is still not well understood. The aim of this review is to examine the contribution of the fundamental components of cardiac excitation-contraction coupling to frequency inotropy in healthy and failing hearts.
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| pubmed:commentsCorrections | |
| pubmed:language |
eng
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| pubmed:journal | |
| pubmed:status |
PubMed-not-MEDLINE
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| pubmed:month |
Dec
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| pubmed:issn |
1443-9506
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| pubmed:author | |
| pubmed:issnType |
Print
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| pubmed:volume |
13
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| pubmed:owner |
NLM
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| pubmed:authorsComplete |
Y
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| pubmed:pagination |
410-20
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| pubmed:year |
2004
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| pubmed:articleTitle |
Pacing staircase phenomenon in the heart: from Bodwitch to the XXI century.
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| pubmed:affiliation |
Centro de Investigaciones Cardiovasculares, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, 60 y 120, La Plata 1900, Argentina.
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| pubmed:publicationType |
Journal Article
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