A system configured to detect at least one location of at least one source of, or rotational phenomenon associated with, at least one cardiac rhythm disorder in a patient's heart, the system comprising: (a) at least one computing device; (b) at least one data acquisition device operably connected to the at least one computing device or configured to provide as outputs therefrom at least one of intracardiac electrophysiological EP mapping signals (EP mapping signals); (c) a display or monitor operably connected to the at least one computing device and configured to visually display to the user one or more maps generated by the at least one computing device; wherein the computing device comprises at least one non-transitory computer readable medium configured to store instructions executable by at least one processor to determine the at least one location of the at least one source of, or rotational phenomenon associated with, the at least one cardiac rhythm disorder in the patient's heart, the computing device being configured to: (i) receive the intracardiac EP mapping signals from at least one of a plurality of intracardiac electrodes located inside the patient's heart, where amplitudes of the intracardiac EP mapping signals received by the at least one computing device have been at least one of conditioned, amplified, normalized, filtered, and adjusted by the data acquisition device before being provided to the computing device; (ii) assign or relate positional data corresponding to predetermined positions of the intracardiac electrodes in the patient's heart to their respective corresponding intracardiac EP mapping signals and intracardiac electrodes; (iii) generate at least one spatial map of at least one of the intracardiac electrode positions; (iv) for each or selected discrete times over which at least one of the intracardiac EP mapping signals are being processed, process the amplitude-adjusted intracardiac EP mapping signals to generate a plurality of electrogram surfaces or data grids, each such surface or data grid corresponding at least partially to the at least one spatial map, at least one surface or data grid being generated for each such time, characterised in that the computing device further is configured to (v) use a modified multi-frame Horn-Schunck algorithm, wherein in each iteration a cost function E = ∫∫ I x u + I y υ + I t 2 + α 2 ∇ u 2 + ∇ υ 2 d x d y for a two-dimensional image stream is minimized, where I x, I y and It are the derivatives of the image intensity values along the x, y and time dimensions respectively, V =[ u ( x, y), v ( x, y)] T is the optical flow vector, and the smoothing parameter α is a regularization constant, employing optical flow information from multiple frames over a time interval dt ranging between about 0.5 ms and about 50 ms; the number of iterations n per frame pair ranging between about 1 and about 20; and the smoothing parameter α ranging between about 1 and about 300; frames, time intervals, periods or segments ranging between about 0.5 s and about 5 s; and the corresponding number of frames analyzed in each time interval, period or segment as a function of the time interval, period, or segment duration and the sampling rate dt ranging between about 3 frames and about 200 frames, to process the plurality of electrogram surfaces or data grids through time to generate at least one map corresponding at least partially to the spatial map, the at least one map being configured to reveal the at least one location of the at least one source of, or rotational phenomenon associated with, the at least one cardiac rhythm disorder, the at least one map being shown to the user on the display or monitor. (a) at least one computing device; (b) at least one data acquisition device operably connected to the at least one computing device or configured to provide as outputs therefrom at least one of intracardiac electrophysiological EP mapping signals (EP mapping signals); (c) a display or monitor operably connected to the at least one computing device and configured to visually display to the user one or more maps generated by the at least one computing device; for a two-dimensional image stream is minimized, where I x, I y and It are the derivatives of the image intensity values along the x, y and time dimensions respectively, V =[ u ( x, y), v ( x, y)] T is the optical flow vector, and the smoothing parameter α is a regularization constant, employing optical flow information from multiple frames over a time interval dt ranging between about 0.5 ms and about 50 ms; the number of iterations n per frame pair ranging between about 1 and about 20; and the smoothing parameter α ranging between about 1 and about 300; frames, time intervals, periods or segments ranging between about 0.5 s and about 5 s; and the corresponding number of frames analyzed in each time interval, period or segment as a function of the time interval, period, or segment duration and the sampling rate dt ranging between about 3 frames and about 200 frames, to process the plurality of electrogram surfaces or data grids through time to generate at least one map corresponding at least partially to the spatial map, the at least one map being configured to reveal the at least one location of the at least one source of, or rotational phenomenon associated with, the at least one cardiac rhythm disorder, the at least one map being shown to the user on the display or monitor.