Torso surface and ventricular epicardial potentials were recorded simultaneously in anesthetized, closed-chest pigs (n=5) during sinus rhythm. Activation times were estimated from recorded torso potentials using three classical ECGI methods and a new method called the Patchwork Method (PM), which locally selects the optimal ECGI method and has demonstrated its efficiency with simulated data. The aim of this study was to evaluate the Patchwork method using experimental data in sinus rhythm. By comparing the classic ECGI reconstructions to recorded epicardial activation mapping, several inaccuracies in the ECGI maps are highlighted in this study. This involved inaccuracies in reconstructing activating maps, locating breakthrough sites and the production of artificial lines of block. However, the PM overcomes these restrictions, demonstrating its abilities to accurately reconstruct activation maps (CC=0.90 [0.86 ; 0.92] and RE= 0.20 [0.19 ; 0.24]) and localize epicardial breakthrough sites (LE= 17.16 [8.87 ; 22.14]). Furthermore, it reduced the frequency of artificial lines of block (2 of 5 pig hearts).