Comparing chloroquine to flecainide. A and B, although flecainide reduces the number of rotations/cm2 at the PLA and LAA (5-sec movies), only chloroquine significantly decrease the number of rotations/cm2 at the PLA. C, the core size does not significantly increase during flecainide. D, Similarly, only chloroquine significantly decreases the number breakthroughs/cm2 at the PLA.