Abstract: A method including: measuring signals at one or more catheter electrodes in response to electrical activity in a heart cavity and collecting additional data signals; defining a template set including information related to the additional data signals; computing criteria for each of the additional data signals based on a comparison of the additional data signals and the template set; synchronizing the measured signals with one another by calculating a single synchronization offset that is a time value based on the computed criteria and the difference between a marker in the template set and a point in the additional data signals; selecting a subset of the synchronized signals by determining whether to include the signals for a heartbeat in the subset based on the computed criteria; and determining physiological information at multiple locations of the endocardium surface based on the measured signals by processing the selected subset.