Atrial Fibrillation (AF) is the most common cardiac rhythm disorder worldwide whereas in Paroxysmal AF (PAF) patients, the leading role for its onset is the underling electrical remodeling. P-wave in electrocardiographic (ECG) signals represents the activation of the atrial substrate. Its shape is influenced by the origin of the sinus rhythm (SR) and the conduction of each part of the atria and thus the analysis of its morphology (PWM) can reveal information related to the atrial conduction routes. Recently, the analysis of the P-waves from ECG signals of PAF patients during SR, revealed the presence of a distinct secondary P-wave morphology in a remarkable percentage of beats, besides the majority of the P-waves matching a main P-wave morphology. We hypothesize that the variability on the PWM can be attributed to the transient modification of the conduction route which is the result of the shift of the pacemaker location within the sinus node (1x1cm).In this study, we incorporated the electrophysiological model of Courtemanche et al. in a 2D tissue describing the left and the right atria, while tissue heterogeneities were also considered. Multiple simulations were conducted, in the normal and electrical remodeled tissue, in each of them the pacemaker location was shifted within the sinus node. The simulation were conducted in CHASTE platform, in order to investigate the conditions under which it is possible to reproduce the different activation pathways in PAF patients while in SR. The initial results seem promising however 3D realistic model of human atria must be considered in order to investigate the reproducibility of the results while longer studies must be conducted in order to reveal the conditions under which the pacemaker location shifts.