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Article: Electrophysiological effects of encainide (MJ9067) on canine subendocardial Purkinje fibers surviving infarction

TitleElectrophysiological effects of encainide (MJ9067) on canine subendocardial Purkinje fibers surviving infarction
Authors
Issue Date1984
PublisherLippincott Williams & Wilkins. The Journal's web site is located at http://www.cardiovascularpharm.com/
Citation
Journal Of Cardiovascular Pharmacology, 1984, v. 6 n. 4, p. 547-554 How to Cite?
AbstractThe electrophysiological effects of encainide (MJ9067) on canine subendocardial Purkinje fibers surviving infarction were examined 22-24 h after coronary artery ligation, using standard microelectrode techniques at pH 7.4. Encainide (5 and 10 μM) shortened APD50, decreased the action potential amplitude and overshoot, caused a 2-3 mV depolarization of the cell, and decreased the maximum rate of phase 0 depolarization. All these effects were dose dependent. APD90 was slightly, but not significantly, shortened. Encainide had a greater effect on APD50 than on APD90 at longer (1,000 ms) stimulation cycle lengths than at shorter (400 ms) cycle lengths. There was a significant interaction between the effects of stimulation rate and encainide concentration on APD90, APD50, amplitude, and overshoot. The same parameters measured at a lower pH (7.1) gave similar results. There was a significant correlation (r = -0.540, p < 0.001) between the control APD90 and the degree and direction of change of APD90 after 10 μM encainide. Automaticity of the infarcted preparations was eliminated or slowed in a dose-dependent fashion by 5 and 10 μM encainide. The curve relating membrane potential and the maximum rate of phase 0 depolarization was shifted down and toward higher potentials by 5 μM encainide. The results show that encainide produces similar changes in the action potentials of Purkinje fibers surviving infarction as in normal Purkinje fibers, and is effective in lowering the rate of spontaneous depolarizations in infarcted tissue. Furthermore, encainide appears to be the only antiarrhythmic drug which has been shown to increase and decrease APD90, depending on the initial APD90 of the cell.
Persistent Identifierhttp://hdl.handle.net/10722/170721
ISSN
2015 Impact Factor: 2.462
2015 SCImago Journal Rankings: 0.962
ISI Accession Number ID

 

DC FieldValueLanguage
dc.contributor.authorKing, BWen_US
dc.contributor.authorMan, RYKen_US
dc.date.accessioned2012-10-30T06:10:35Z-
dc.date.available2012-10-30T06:10:35Z-
dc.date.issued1984en_US
dc.identifier.citationJournal Of Cardiovascular Pharmacology, 1984, v. 6 n. 4, p. 547-554en_US
dc.identifier.issn0160-2446en_US
dc.identifier.urihttp://hdl.handle.net/10722/170721-
dc.description.abstractThe electrophysiological effects of encainide (MJ9067) on canine subendocardial Purkinje fibers surviving infarction were examined 22-24 h after coronary artery ligation, using standard microelectrode techniques at pH 7.4. Encainide (5 and 10 μM) shortened APD50, decreased the action potential amplitude and overshoot, caused a 2-3 mV depolarization of the cell, and decreased the maximum rate of phase 0 depolarization. All these effects were dose dependent. APD90 was slightly, but not significantly, shortened. Encainide had a greater effect on APD50 than on APD90 at longer (1,000 ms) stimulation cycle lengths than at shorter (400 ms) cycle lengths. There was a significant interaction between the effects of stimulation rate and encainide concentration on APD90, APD50, amplitude, and overshoot. The same parameters measured at a lower pH (7.1) gave similar results. There was a significant correlation (r = -0.540, p < 0.001) between the control APD90 and the degree and direction of change of APD90 after 10 μM encainide. Automaticity of the infarcted preparations was eliminated or slowed in a dose-dependent fashion by 5 and 10 μM encainide. The curve relating membrane potential and the maximum rate of phase 0 depolarization was shifted down and toward higher potentials by 5 μM encainide. The results show that encainide produces similar changes in the action potentials of Purkinje fibers surviving infarction as in normal Purkinje fibers, and is effective in lowering the rate of spontaneous depolarizations in infarcted tissue. Furthermore, encainide appears to be the only antiarrhythmic drug which has been shown to increase and decrease APD90, depending on the initial APD90 of the cell.en_US
dc.languageengen_US
dc.publisherLippincott Williams & Wilkins. The Journal's web site is located at http://www.cardiovascularpharm.com/en_US
dc.relation.ispartofJournal of Cardiovascular Pharmacologyen_US
dc.subject.meshAction Potentials - Drug Effectsen_US
dc.subject.meshAnilides - Pharmacologyen_US
dc.subject.meshAnimalsen_US
dc.subject.meshAnti-Arrhythmia Agents - Pharmacologyen_US
dc.subject.meshDogsen_US
dc.subject.meshElectric Stimulationen_US
dc.subject.meshElectrophysiologyen_US
dc.subject.meshEncainideen_US
dc.subject.meshFemaleen_US
dc.subject.meshHeart Conduction System - Drug Effectsen_US
dc.subject.meshHydrogen-Ion Concentrationen_US
dc.subject.meshMaleen_US
dc.subject.meshMembrane Potentials - Drug Effectsen_US
dc.subject.meshMyocardial Infarction - Physiopathologyen_US
dc.subject.meshPurkinje Fibers - Drug Effectsen_US
dc.titleElectrophysiological effects of encainide (MJ9067) on canine subendocardial Purkinje fibers surviving infarctionen_US
dc.typeArticleen_US
dc.identifier.emailMan, RYK:rykman@hkucc.hku.hken_US
dc.identifier.authorityMan, RYK=rp00236en_US
dc.description.naturelink_to_subscribed_fulltexten_US
dc.identifier.doi10.1097/00005344-198407000-00001-
dc.identifier.pmid6206306-
dc.identifier.scopuseid_2-s2.0-0021141661en_US
dc.identifier.volume6en_US
dc.identifier.issue4en_US
dc.identifier.spage547en_US
dc.identifier.epage554en_US
dc.identifier.isiWOS:A1984TB11800001-
dc.publisher.placeUnited Statesen_US
dc.identifier.scopusauthoridKing, BW=7402688421en_US
dc.identifier.scopusauthoridMan, RYK=7004986435en_US

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