Cardiac activation wavefronts can be computed as one or more stream paths or stream lines from electrophysiological data collected by a multi-electrode catheter. In embodiments of the disclosure, the stream path or stream line is computed by identifying a first activating bipole from amongst the electrodes and then iteratively identifying successively later-activating, neighboring bipoles. The process can be repeated for additional bipoles and/or additional locations of the multi-electrode catheter within the subject's heart. In additional embodiments of the disclosure, stream paths or stream lines are computed from a conduction velocity vector field or mesh, distributed over a cardiac geometry, by identifying the path of one or more seed points through the conduction velocity vector field. The stream paths and/or stream lines can be graphically output, such as on a three-dimensional cardiac geometry model.