Figure 7.
Effect of ranolazine to suppress d-sotalol-induced early afterdepolarizations (EAD) in M cell and Purkinje fiber preparations. A: Shown are superimposed transmembrane action potentials recorded from a Purkinje fiber preparation in the presence of IKr block (100 μM d-sotalol), and following addition of increasing concentrations of ranolazine (5 and 10 μM) in the continued presence of d-sotalol. [K+]o=3 mM. BCL=8000 ms and B: Superimposed transmembrane action potentials recorded from an M cell preparation under control conditions, in the presence of IKr block (100 μM d-sotalol), and following increasing concentrations of ranolazine (5, 10, and 20 μM) in the continued presence of d-sotalol. BCL=2000 ms.