These images show electrical activation maps acquired on a registered image of the patient’s left atrium. The activation sequence is colour-coded, with red indicating early, purple late with green and blue in between. It is apparent that there is an ‘early-meets-late’ area on the anterolateral mitral valve annulus. Entrainment data confirmed that this was a peri-mitral flutter. Treated successfully with creating an anterior mitral line (joining to the left upper pulmonary vein, LUPV) and the posterior mitral line (joining to the left lower pulmonary vein, LLPV). Both the veins were isolated to provide anchors for the linear lesions.

The patient has been in sinus rhythm subsequently.