Figure 3.

Bretylium + cromakalim. In these experiments, cromakalim was added to prevent APD prolongation by bretylium. (A) Compared with control (○ and thin lines), bretylium + cromakalim (● and thick lines) flattened APDR measured by the dynamic pacing method (a and b) and APDR during VF (c). (d) Superimposed APDR slopes before (thin lines) and after bretylium + cromakalim (thick lines) in all five preparations. (B) Transmembrane potential recording during the transition from VF to VT. (C) Gray-scale maps of voltage during VF (Left) and after bretylium + cromakalim (Right). Arrow shows fiber direction.