Salicylaldoxime blocks K+ and Ca2+ currents in rat cardiac myocytes.

The effects of salicylaldoxime, 2-(OH)C6H4CH = NOH, on the action potential duration, transient outward K+ current and slow inward Ca2+ current were studied in isolated rat ventricular myocytes. The application of salicylaldoxime (0.1-2.0 mM) reversibly increased the action potential duration and reduced in a dose-dependent manner both the transient outward K+ and the slow inward Ca2+ currents. The effect of salicylaldoxime on these two ionic currents was similar to that of 2,3-butanedione monoxime, but was about ten times more potent. Compounds which block both K+ and Ca2+ currents may represent a new type of Class III antiarrhythmic agent which counteracts arrhythmias initiated by re-entry with reduced proarrhythmic risk via triggered activity.