In this 61 year old man with persistent AF, unipolar AF electrograms confirm rotation around rotor core. A) Electrograms (unipoles) and dV/dt (first derivative, green) shown, with one cycle annotated (red lines). B) Left atrial shell with activation map from the annotated cycle, demonstrating earliest-latest interaction in a rotational pattern. C) Termination panel shows abrupt termination of AF to organized AT with ablation at this site, prior to any PVI. Black bar represents 1000ms. D) Location on LA posterior wall of termination site (red) during ablation of rotor area (white).