An implantable stimulation device that maps the location of irritable foci causing an atrial arrhythmia is provided by certain embodiments disclosed herein. The device may, for example, collect intra-cardiac data from a plurality of electrodes spatially distributed throughout a chamber of the heart. This data may be compared with data related to the location of each electrode and the electrical properties of the heart to approximate a point of origin for the atrial arrhythmia. Further embodiments may provide methods and systems for using this information to provide more efficient treatment of the atrial arrhythmia. For example, an optimized ATP pulse train may be determined based on the location of one or more irritable foci. Such an ATP pulse train may be applied to more efficiently terminate the atrial arrhythmia.