Ajmaline

An alkaloid; inhibits hERG/Kv11.1, Kv1.5, and Kv4.3 (IC50s = 42.3, 293, and 186 µM, respectively, in Xenopus oocytes expressing the channels); increases the action potential duration in isolated dog atrium and ventricle at 1 µg/ml; increases the functional refractory duration in the atrium, ventricle, and atrioventricular conduction system in anesthetized dogs at 1 mg/kg, i.v.; reduces the number of premature ventricular complexes and decreases the duration of ventricular tachycardia and ventricular fibrillation in coronary artery-ligated anesthetized rats at 2 mg/kg, i.v.