Alpha-2 adrenergic antagonism enhances risk of ventricular tachycardia during acute ischemia

2.50
Hdl Handle:
http://hdl.handle.net/2336/29717
Title:
Alpha-2 adrenergic antagonism enhances risk of ventricular tachycardia during acute ischemia
Authors:
Arnar, David O; Xing, Dezhi; Martins, James B
Citation:
Scand. Cardiovasc. J. 2007, 41(6):378-85
Issue Date:
1-Dec-2007
Abstract:
OBJECTIVE: In this study we tested the hypothesis that alpha-2 adrenergic antagonism could facilitate induction of previously non-inducible ventricular tachycardia (VT) during acute ischemia. Previous reports suggest that VT during ischemia may be modulated by (alpha-2 adrenergic agonists. DESIGN: The left anterior descending artery was occluded after instrumentation of the ischemic risk zone with 21 multipolar plunge needles, each recording 6 bipolar electrograms. Three dimensional mapping characterized the mechanism of VT induced with extrastimuli. RESULTS: Of 16 non-inducible dogs included, eight which were given the alpha-2 adrenergic antagonist yohimbine all had inducible VT, while all eight in the control group remained non-inducible (p < 0.05). Six of the VTs were of focal Purkinje origin. The cycle length of the VTwas 119 +/- 4 ms. Mean arterial pressure (81+/- 8 to 82 +/- 8 mmHg, p = ns), ventricular effective refractory period (146 +/- 6 to 144 +/- 5 ms, p = ns) and ischemic zone size (55 +/-6% vs. 61 +/- 4%, p = 0.45) were not altered by yohimbine indicating minimal central or pre-junctional effects of the drug. CONCLUSIONS: Yohimbine facilitates induction of VT, especially those with focal Purkinje fiber origin, suggestive of an effect mediated through antagonism of post-junctional alpha-2 adrenoceptors on Purkinje fibers.
Description:
To access publisher full text version of this article. Please click on the hyperlink in Additional Links field
Additional Links:
http://dx.doi.org/10.1080/14017430701487713

Full metadata record

DC FieldValue Language
dc.contributor.authorArnar, David O-
dc.contributor.authorXing, Dezhi-
dc.contributor.authorMartins, James B-
dc.date.accessioned2008-06-09T14:56:48Z-
dc.date.available2008-06-09T14:56:48Z-
dc.date.issued2007-12-01-
dc.date.submitted2008-06-09-
dc.identifier.citationScand. Cardiovasc. J. 2007, 41(6):378-85en
dc.identifier.issn1401-7431-
dc.identifier.pmid17852790-
dc.identifier.doi10.1080/14017430701487713-
dc.identifier.urihttp://hdl.handle.net/2336/29717-
dc.descriptionTo access publisher full text version of this article. Please click on the hyperlink in Additional Links fielden
dc.description.abstractOBJECTIVE: In this study we tested the hypothesis that alpha-2 adrenergic antagonism could facilitate induction of previously non-inducible ventricular tachycardia (VT) during acute ischemia. Previous reports suggest that VT during ischemia may be modulated by (alpha-2 adrenergic agonists. DESIGN: The left anterior descending artery was occluded after instrumentation of the ischemic risk zone with 21 multipolar plunge needles, each recording 6 bipolar electrograms. Three dimensional mapping characterized the mechanism of VT induced with extrastimuli. RESULTS: Of 16 non-inducible dogs included, eight which were given the alpha-2 adrenergic antagonist yohimbine all had inducible VT, while all eight in the control group remained non-inducible (p < 0.05). Six of the VTs were of focal Purkinje origin. The cycle length of the VTwas 119 +/- 4 ms. Mean arterial pressure (81+/- 8 to 82 +/- 8 mmHg, p = ns), ventricular effective refractory period (146 +/- 6 to 144 +/- 5 ms, p = ns) and ischemic zone size (55 +/-6% vs. 61 +/- 4%, p = 0.45) were not altered by yohimbine indicating minimal central or pre-junctional effects of the drug. CONCLUSIONS: Yohimbine facilitates induction of VT, especially those with focal Purkinje fiber origin, suggestive of an effect mediated through antagonism of post-junctional alpha-2 adrenoceptors on Purkinje fibers.en
dc.language.isoenen
dc.publisherTaylor & Francisen
dc.relation.urlhttp://dx.doi.org/10.1080/14017430701487713en
dc.subject.meshAdrenergic alpha-Antagonistsen
dc.subject.meshMyocardial Ischemiaen
dc.titleAlpha-2 adrenergic antagonism enhances risk of ventricular tachycardia during acute ischemiaen
dc.typeArticleen
dc.contributor.departmentDepartment of Medicine, Landspitali University Hospital, Hringbrauten
dc.identifier.journalScandinavian cardiovascular journal : SCJen
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