Ectopic atrial activity underlies atrial tachycardia (AT), which, may predispose to atrial fibrillation (AF). Such abnormal excitation may be reflected as an alteration in the P-wave morphology (PWM) of the body surface potential (BSP). Identifying the location of the ectopic foci from body surface potential maps, can help to diagnose the early onset of AF in a cost effective manner. However, the correlation between the PWM of BSP and the origin of atrial foci has not been well established. In this study we use a biophysically detailed computational model of the human atria and torso to investigate such correlations.