Information GS967 GS967 (GS458967) is a potent and selective inhibitor of late I Na with anti-arrhythmic actions. Targets late INa 0.13 μM In vitro GS967 (3 μM) has no significant effect on L- or T-type calcium channel currents or Na+-Ca2+ exchanger current (INCX), and 1 μM GS967 has minimal or no effect on the ATP-inhibited K+ current or on human cardiac ion channels expressed in human embryonic kidney 293 or Chinese hamster ovary cells. GS967 is a novel sodium channel modulatorspecifically developed to inhibit persistent sodium current, with a 42-fold preference for persistent as opposed to peakcurrent inhibition. In vivo GS967 protects against seizures and prematurelethality in vivo. Chronic GS967 does not cause overt behavioraltoxicity or sedation in wild-type mice at theeffective anticonvulsant dose. GS967 suppresses arrhythmogenicity evoked by ischemia, hypokalemia, and catecholamines in canine and porcine models.