Document Detail

Effects of adrenaline on electrophysiological parameters during short exposure to global ischemia. A ventricular fibrillation study in isolated heart.
MedLine Citation:
PMID:  12090903     Owner:  NLM     Status:  MEDLINE    
BACKGROUND: The mechanisms by which adrenaline may enhance defibrillation success rate, is poorly understood. OBJECTIVES: To study electrophysiological effects of adrenaline during short exposure to global ischemia. METHODS: In isolated perfused feline hearts, coronary perfusion was eliminated repeatedly for 1 min with 10 min reperfusion intervals. Treatment included: (1) continuous perfusion alone-control, (2) global ischemia alone, (3) adrenaline (10(-7) M) during perfusion, (4) adrenaline (10(-7) M) during global ischemia (n = 10), in separate hearts, (5) control and higher adrenaline concentration (1 x 10(-6) M), (6) during perfusion, (7) during global ischemia (n = 9). Measurements during pacing included: (1) diastolic threshold of excitability; (2) refractoriness; (3) epicardial conduction time; and (4) all tissue resistivity to indirectly detect changes in passive properties of conduction. Measurements during 1 min (or 90 sec) of electrically induced ventricular fibrillation included-all tissue resistivity and, based on maximal entropy spectral analysis and normalized entropy, rate of arrhythmia and degree of arrhythmia organization. RESULTS: Adrenaline (10(-7) M) during global ischemia vs control caused spontaneous arrhythmia termination, increased threshold significantly but reduced conduction time. Higher adrenaline concentration (1 x 10(-6) M) during global ischemia improved the passive properties of conduction and arrhythmia organization and reduced arrhythmia rate. Global ischemia alone increased conduction time but had a deleterious effect on passive properties. Adrenaline (10(-7) M) during perfusion improved conduction, but did so less than during global ischemia. Higher adrenaline concentration during perfusion (10(-6) M) improved arrhythmia organization and caused spontaneous arrhythmia termination but again less than during global ischemia. CONCLUSIONS: During short periods of global ischemia adrenaline improved the passive properties of conduction and arrhythmia organization, reduced arrhythmia rate and increased its spontaneous termination. Such changes may be operative in improving defibrillation success.
Giora Amitzur; Nitza Shenkar; Jonathan Leor; Ilia Novikov; Michael Eldar
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Publication Detail:
Type:  Comparative Study; In Vitro; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Cardiovascular drugs and therapy / sponsored by the International Society of Cardiovascular Pharmacotherapy     Volume:  16     ISSN:  0920-3206     ISO Abbreviation:  Cardiovasc Drugs Ther     Publication Date:  2002 Mar 
Date Detail:
Created Date:  2002-07-01     Completed Date:  2003-03-28     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  8712220     Medline TA:  Cardiovasc Drugs Ther     Country:  United States    
Other Details:
Languages:  eng     Pagination:  111-9     Citation Subset:  IM    
Neufeld Cardiac Research Institute, Tel-Aviv University, Tel-Hashomer, Israel.
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MeSH Terms
Adrenergic beta-Agonists / pharmacology*
Analysis of Variance
Dose-Response Relationship, Drug
Electrophysiologic Techniques, Cardiac
Epinephrine / pharmacology*,  physiology
Myocardial Ischemia / complications*
Tachycardia / etiology,  physiopathology
Ventricular Fibrillation / etiology,  physiopathology*
Reg. No./Substance:
0/Adrenergic beta-Agonists; 51-43-4/Epinephrine

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