Activation (A) and propagation (B–F) maps of the right atrium during AT in a patient with surgically repaired Tetralogy of Fallot. In A, the MDI is localized (dark red band) in the low lateral region. In B through F, sequential frames of the propagation map show the two wavefronts (yellow and green arrows) exiting from the MDI and rotating clockwise around the line of atriotomy (blue dots for double potentials) and counter-clockwise around the tricuspid annulus, respectively. These maps identify the presence of a double-loop reentry with both loops sharing the same MDI. Red dots indicate the ablation line along the MDI.