Depolarization sequences triggering mechanical contraction of the heart are largely determined by the cardiac conduction system (CS). Many biophysical models of cardiac electrophysiology still have poor representations of the CS. This work proposes a semiautomatic method for the generation of an anatomically-realistic porcine CS that reproduces ventricular activation properties in swine computational models. Personalized swine biventricular models were built from magnetic resonance images. Electrical propagation was described by the monodomain model. The CS was defined from manually-determined anatomic landmarks using geodesic paths and a fractal tree algorithm. Two CS distributions were defined, one restricted to the subendocardium and another one by performing a subendo-to-intramyocardium projection based on histological porcine data. Depolarization patterns as well as left ventricular transmural and inter-ventricular delays were assessed to describe ventricular activation by the two CS distributions. The electrical excitations calculated using the two CS distributions were in good agreement with reported activation patterns. The pig-specific subendo-intramyocardial CS led to improved reproduction of experimental activation delays in ventricular endocardium and epicardium
