The present invention concerns a system (100) for analyzing electrophysiological data, especially intracardial electrogram data, the system (100) comprising a data processing and control unit (15) for processing the electrophysiological data, a data output unit comprising a data output screen (324) for displaying results of electrophysiological data analysis, wherein the data processing and control unit (15) being configured to receive electrophysiological data obtained from a mapping catheter assembly (110, 111) that comprises an electrode assembly (120, 80) with a plurality of n electrodes (82), each electrode (82) configured for measuring electrophysiological data in the form of electrogram signals. The data processing and control unit (15) comprises an engine for performing an optical flow analysis of the electrophysiological data to generate series of vector data (40) representing the average speed and direction of movement of clusters of the electrophysiological data, the data output unit being configured to display the vector data on a data output screen (324) of the data output unit.