Intraoperative epicardial mapping. Activation maps of VT constructed by intraoperative electro-anatomical mapping are shown. Colour-coded contours represent ventricular activation during VT; from the earliest activation as red to the latest activation as purple. The patient presented with 2 different QRS morphologies of VT; one originated from the anterior left ventricle beneath the proximal LAD and the other from the lateral left ventricle beneath the proximal LCX. AIV: anterior interventricular vein; Asc. AO: ascending aorta; LAA: left atrial appendage; LAD: left anterior descending coronary artery; LCA: left coronary artery; LCX: left circumflex coronary artery; OM: obtuse marginal branch of the left circumflex coronary artery; PA: pulmonary artery; RVOT: right ventricular outflow tract; VT: ventricular tachycardia.