Key result
Epicardial DFT drops ~53% from day 1 to day 2, partially reversed by propranolol.
Why the study?
Day-to-day variations in epicardial defibrillation threshold and the adrenergic influences on these variations in closed-chest, unanesthetized dogs were not well characterized.
Does adrenergic modulation with propranolol or isoproterenol alter the epicardial defibrillation threshold in unanesthetized dogs?
Population
11 closed-chest, unanesthetized dogs
Comparison
Baseline DFT vs DFT after propranolol and/or isoproterenol administration
Design
Experimental study in unanesthetized dogs
Follow-up
5 consecutive days
Authors
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Adrenergic modulation of defibrillation threshold merits human study; leaves open translation from this animal model.
Does adrenergic modulation with propranolol or isoproterenol alter the epicardial defibrillation threshold in unanesthetized dogs?
Absolute Event Rate: 7.4% vs 15.8%
p-value: p=<0.0001
Adrenergic tone significantly modulates the epicardial defibrillation threshold in unanesthetized dogs, with beta-blockade increasing and beta-stimulation decreasing the energy required.
Ruffy et al. (1986) studied Epicardial defibrillation. Time (Day 2 vs Day 1) and adrenergic agents (propranolol, isoproterenol) vs. Baseline (Day 1) was evaluated on Epicardial defibrillation threshold (DFT) (p=<0.0001). In closed-chest, unanesthetized dogs, epicardial defibrillation threshold decreased significantly from day 1 to day 2 (15.8 to 7.4 J, p<0.0001), an effect partially reversible by propranolol.
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