| Age related differences in the response to acidosis, hypoxia, and hyperkalaemia in canine cardiac Purkinje fibers. | |
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MedLine Citation:
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PMID: 8111781 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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OBJECTIVE: In the clinical setting, the response of adult and neonatal cardiac rhythms to hypoxia and to acidosis differs, the former leading to tachyarrhythmias and the latter to bradyarrhythmias. In this study, the aim was to determine whether a cellular electrophysiological substrate could be identified to explain the clinical observation. METHODS: Conventional microelectrode techniques were used to study the electrophysiological responses of automatic Purkinje fibres to acidosis, hypoxia, and hyperkalaemia individually. RESULTS: Adult Purkinje fibres showed decreases in maximum diastolic potential, activation voltage, and automaticity as pH was decreased from 7.3 to 6.1. Triggered activity due to early afterdepolarisations developed in 70% of adult Purkinje fibres at pH 6.1. Neonatal Purkinje fibres showed decreased automaticity as pH decreased and, in contrast to adults, quiescence occurred at pH 6.1 At PO2 < 2.9 kPa automaticity decreased significantly in adult Purkinje fibres, whereas neonatal fibres were unaffected. The effect of raising [K+]o was comparable at both ages. CONCLUSIONS: The response to acidosis and to hypoxia differs significantly between neonatal and adult Purkinje fibres and may explain some developmental differences in the expression of cardiac arrhythmias. |
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Authors:
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J C Geller; M R Rosen |
Publication Detail:
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Type: Comparative Study; Journal Article |
Journal Detail:
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Title: Cardiovascular research Volume: 28 ISSN: 0008-6363 ISO Abbreviation: Cardiovasc. Res. Publication Date: 1994 Jan |
Date Detail:
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Created Date: 1994-03-30 Completed Date: 1994-03-30 Revised Date: 2006-11-15 |
Medline Journal Info:
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Nlm Unique ID: 0077427 Medline TA: Cardiovasc Res Country: ENGLAND |
Other Details:
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Languages: eng Pagination: 125-8 Citation Subset: IM |
Affiliation:
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Department of Pharmacology, Columbia University, New York, NY 10032. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Acidosis
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physiopathology* Aging / physiology* Animals Anoxia / physiopathology* Dogs Electrophysiology Female Hyperkalemia / physiopathology* Male Purkinje Fibers / physiopathology* |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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