37F with Hx of ASD s/p surgical repair presents with palpitation.
EGM shows AFL/AT CL 230ms with 4:1 AV block.
Entrainment favors the circuit location around low lateral RA.
3D electroanatomical mapping shows the flutter circuit around
the atriotomy scar at lateral RA. Linear ablation from the scar to IVC terminates the tachycardia.