Fig. 1

Epicardial ablation. (A, B) Both present a modified left lateral view of a partial three-dimensional (3D) electro-anatomical mapping (EAM) voltage map of the epicardial part of the left ventricle (LV) with purple dots representing local abnormal ventricular activity (LAVA) sites inside and on the border of the low voltage area and red dots representing eventual ablation lesions. The white arrows mark the approximate location of the recorded LAVA as shown on intra-cardiac electrogram recordings made with multipolar mapping catheter presented on (C) (Pentaray 1–20) and with ablation catheter presented on (D) (ABLD and ABLP). The white asterisks mark the recorded isolated diastolic potentials at one of the eventual ablation sites near the course of the left circumflex artery (LCX) at the base of the epicardial side of the left ventricle. Before ablation at that site, selective left coronary angiography in a modified right anterior oblique view was performed as shown on (E, F). Red arrow on (E) points at the tip of the ablation catheter touching the proximal part of the LCX in which case the catheter was slightly withdrawn to the site marked with the white arrow on (F) showing the tip at the safe distance from the LCX at the location of the eventual successful ablation. CSD-CSP intra-cardiac electrograms recorded with a 10-polar diagnostic catheter in the right ventricle; I, II, aVF and V1 surface electrograms