In a system and computer implemented method for mapping of an anatomic structure and bi-directional activation detection of electrograms such as atrial and/or ventricular electrograms, both positive and negative deflections of an electrogram signal are analyzed over an analysis time period of the signal. At least one characteristic of the electrogram signal is determined based at least in part on analyzing both positive and negative deflections of the signal over the analysis time period. The determined at least one characteristic of the atrial electrogram signal is then associated with a generated three-dimensional model of the anatomic structure.
