Ablation points and corresponding parameters (patient 1). (A) Images from the Biosense Webster CARTO 3 mapping system indicating the ablation points (round balls) in right and left anterior oblique views, in the left- and right-hand images, respectively. The final ablation point at the anterior aspect of the coronary sinus lip (larger spherical lesions) resulted in the loss of pre-excitation. (B) Ablation parameters for each point, with 5 being the final location when loss of pre-excitation was observed. (C) Comparison of the electrocardiogram signals at the start of ablation at the final location (left) and 6 s into ablation (right) when loss of the delta wave was observed with split atrial and ventricular signals (Map1-2). The surface ECG (I, II, aVF, aVL, V1, V4, and V6), ablation catheter (Map 1-2 and 3-4), and quadrapolar (Quad 1-2 and 3-4) catheter (placed in the coronary sinus) signals are shown in blue, white, and red colours respectively. Avg, average; g, grams; s, seconds; W, watts; Ω, ohms.