System for filtering cardiac signals, the system comprising: a plurality of cardiac terminals (10a-d) adapted to collect cardiac electrophysiological potentials from a plurality of cardiac electrodes (1a-d) placed at respective cardiac locations in or on an individual (99) and a processor device (40) adapted to process one or more input signals which are based on the collected electrophysiological potential(s). The processing comprises running an adaptive filter algorithm on one or more signals based on the input signals, said adaptive filter algorithm being arranged to calculate one or more estimated noise component(s) of said one or more signals and being arranged to subtract said one or more estimated noise component(s) respectively from said one or more signals. In this way a cardiac signal is derived where the noise has been significantly reduced.
