Proarrhythmic effects of DPI 201-106 elicited with programmed electrical stimulation: a comparison with sotalol.

Among antiarrhythmic agents, those belonging to class III are considered most promising. Class III drugs act by prolonging the action potential duration (APD), which increases the effective refractory period (ERP). This effect can be achieved by several different cellular mechanisms. We hypothesized that among other variables the mechanism of action could be important for the propensity of class III agents to have proarrhythmic effects. We investigated the effects of sotalol (a potassium channel blocker) and DPI 201-106 (DPI, an activator of sodium channels) at doses causing the same increase in ERP, using programmed electrical stimulation (PES) in open-chest rabbits