Modification of Ventricular Fibrillation
نویسنده
چکیده
Abrupt occlusion of the left anterior descending coronary artery was performed on 43x unanesthetized farm pigs in order to evaluate the relative effects on the latency to ventricular fibrillation (\VFL) of 1 ) adaptation of the animals to the laboratory, and 2) beta-receptor blockade by propranolol. Compared to control values, VFL, was greatly lengthened (i.e., VF delayed or prevented) by adaptation (P < 0.01), was shortened bv large (2 mg/kg) doses of racemic propranolol in unadapted animals (P < 0.02), and was again increased, while under the influence of this drug, by adaptation (P < 0.05). Neither a lower (0.2 mg kg) dose of racemic propranolol, 2 mg/kg of dextropropranolol, nor ventricular pacing to a higher heart rate had an effect on VFL. The results suggest that reduced psychological stress was very effective in retarding or preventing the onset of VF, that low doses of propranolol were ineffective, and that higher doses were deleterious in unadapted animals.
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