Abstract |
The aim of this study was to compare the effects of d- and dl- sotalol on the ventricular fibrillation threshold (VFT) and the effective refractory period (VERP) in anaesthetized cats subjected to coronary artery occlusion. Occlusion of the left anterior descending coronary artery caused a decrease in VFT (measured in mA) (1.40 +/- 0.1 to 0.6 +/- 0.1). dl- Sotalol (1 and 5 mg kg-1) increased VFT before the induction of ischaemia (1.7 +/- 0.1 to 33.8 +/- 1.0 and 38, respectively), and the higher dose prevented the ischaemia-induced fall in VFT. d- Sotalol (1 and 5 mg kg-1) caused only small increases in VFT in normal (1.9 +/- 0.3 to 2.3 +/- 0.3 and 2.6 +/- 0.3) and ischaemic (0.8 +/- 0.1 to 1.2 +/- 0.2 and 1.3 +/- 0.2) myocardium. Both d- and dl- sotalol increased VERP measured in normal myocardium. The % changes observed with 1 and 5 mg kg-1 of the racemate (17 +/- 1 and 57 +/- 4) were significantly greater than those with the d-isomer (8 +/- 3 and 16 +/- 2). dl- Sotalol, but not d- sotalol, prevented the haemodynamic responses to 50 ng kg-1 isoprenaline. These results suggest that VFT in anaesthetized cats is markedly increased by beta- adrenoceptor blockade and only marginally increased by the direct class III antiarrhythmic action of d- sotalol.
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Authors | Y W Kwan, A M Solca, M Gwilt, K A Kane, R M Wadsworth |
Journal | Journal of cardiovascular pharmacology
(J Cardiovasc Pharmacol)
Vol. 15
Issue 2
Pg. 233-8
(Feb 1990)
ISSN: 0160-2446 [Print] United States |
PMID | 1689418
(Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't)
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Chemical References |
- Adrenergic beta-Antagonists
- Anti-Arrhythmia Agents
- Sotalol
- Isoproterenol
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Topics |
- Adrenergic beta-Antagonists
- Animals
- Anti-Arrhythmia Agents
- Cats
- Coronary Disease
(physiopathology)
- Female
- Heart
(drug effects)
- Heart Rate
(drug effects)
- Heart Ventricles
(drug effects)
- In Vitro Techniques
- Isoproterenol
(pharmacology)
- Male
- Papillary Muscles
(drug effects)
- Sotalol
(pharmacology)
- Stereoisomerism
- Ventricular Fibrillation
(physiopathology)
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