| Endurance Exercise Training Normalizes Repolarization and Calcium Handling Abnormalities Preventing Ventricular Fibrillation in a Model of Sudden Cardiac Death. | |
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MedLine Citation:
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PMID: 23042911 Owner: NLM Status: Publisher |
Abstract/OtherAbstract:
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The risk of sudden cardiac death is increased following myocardial infarction (MI). Exercise training reduces arrhythmia susceptibility but the mechanism is unknown. We used a canine model of sudden cardiac death (healed infarction, with ventricular tachyarrhythmias induced by an exercise plus ischemia test, VF+); we previously reported that endurance exercise training was antiarrhythmic in this model. A total of 41 VF+ animals were studied, after random assignment to 10 weeks of endurance exercise training (EET, n=21) or a matched sedentary period (n=20). Following (> 1 week) the final attempted arrhythmia induction, isolated myocytes were used to test the hypotheses that the endurance exercise-induced antiarrhythmic effects resulted from normalization of cellular electrophysiology and/or normalization of calcium handling. EET prevented VF and shortened in vivo repolarization (P<0.05). EET normalized action potential duration and variability compared to the sedentary group. EET resulted in a further decrement in I(to) compared to the sedentary VF+ group (P<0.05). Sedentary VF+ dogs had a significant reduction in I(Kr), which was restored by exercise training (P<0.05). Compared to controls, myocytes from the sedentary VF+ group displayed calcium alternans, increased calcium spark frequency, and increased phosphorylation of S2814 on RyR2. These abnormalities in intracellular calcium handling were attenuated by exercise training (P<0.05). Exercise training prevented ischemically-induced VF in association with a combination of beneficial effects on cellular electrophysiology and calcium handling. |
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Authors:
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Ingrid M Bonilla; Andriy Belevych; Arun Sridhar; Yoshinori Nishijima; Hsiang-Ting Ho; Quanhua He; Monica Kukielka; Dmitry Terentyev; Radmila Terentyeva; Bin Liu; Victor P Long; Sandor Gyorke; Cynthia A Carnes; George E Billman |
Publication Detail:
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Type: JOURNAL ARTICLE Date: 2012-10-4 |
Journal Detail:
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Title: Journal of applied physiology (Bethesda, Md. : 1985) Volume: - ISSN: 1522-1601 ISO Abbreviation: J. Appl. Physiol. Publication Date: 2012 Oct |
Date Detail:
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Created Date: 2012-10-8 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 8502536 Medline TA: J Appl Physiol Country: - |
Other Details:
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Languages: ENG Pagination: - Citation Subset: - |
Affiliation:
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1The Ohio State University. |
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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