Key result
Moderate digitalis slows AFib via atropine-reversible vagal tone, whereas large doses act extravagally.
Why the study?
The relationship between cardiac slowing and circulatory improvement produced by digitalis in patients with auricular fibrillation is unclear and debated.
Does preventing cardiac slowing with atropine alter the improvement of heart failure by digitalis in patients with auricular fibrillation?
Population
Patients with auricular fibrillation
Comparison
Massive dose of digitalis with and without repeated doses of atropine
Design
Other study design
Follow-up
Several days
Authors
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Distinguishes dose-dependent vagal versus extravagal digitalis effects on rate in AF; leaves open whether slowing drives heart failure benefit.
Does preventing cardiac slowing with atropine alter the improvement of heart failure by digitalis in patients with auricular fibrillation?
This study aimed to investigate whether the clinical improvement from digitalis in atrial fibrillation is directly caused by ventricular rate slowing by using atropine to prevent the slowing.
Gold et al. (1939) studied Auricular fibrillation (n=9). Atropine after Digitalis vs. Pre-atropine baseline was evaluated on Percentage of digitalis-induced ventricular slowing abolished by atropine. In patients with auricular fibrillation, ventricular slowing by moderate doses of digitalis is predominantly vagal and abolished by atropine, whereas slowing by large doses is predominantly extravagal and not prevented by atropine.
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