The effect of bretylium on intracellular cardiac action potentials in relation to its anti‐arrhythmic and local anaesthetic activity

Isolated rabbit atria, frog nerves, and anaesthetized guinea-pigs

Bretylium tosylate (concentrations up to 2,400 mg/l in vitro; 20 mg/kg intravenously or 30 mg/kg subcutaneously in vivo)

Procaine and propranolol (for local anaesthetic activity comparison); baseline/control for ouabain infusion

Electrophysiological parameters (conduction velocity, contraction heights, spontaneous frequency, maximum driven frequency, electrical threshold, action potential) and dose of ouabain required to induce arrhythmiassurrogate