Abstract: Systems and methods are disclosed for visualizing reentrant circuits in the heart via pseudo-activation maps. Techniques disclosed comprise receiving sets of ECG data and respective pacing sites. Each of the sets is generated by pacing heart tissue at a respective site of the pacing sites. Techniques disclosed further comprise computing correlation gradients representative of morphological changes across sets, of the sets of the ECG data, of respective neighboring sites of the pacing sites. Based on the computed correlation gradients, a core zone associated with a reentrant circuit is identified. Then, relative to the identified core zone, one or more pseudo-activation maps are generated.