1. A system for the analysis of electrocardiogram (ECG) signals, the system comprising: at least one readout channel, configured to receive an analogue ECG signal acquired from at least one electrode attached to a body, and to extract analogue signals comprising an analogue measured ECG signal and analogue electrode-skin impedance signals; at least one analogue to digital converter (ADC), configured to convert the extracted analogue signals at the readout channel into digital signals; a digital adaptive filter unit, configured to calculate a digital motion artifact estimate based on said digital versions of the measured ECG signal and the electrode-skin impedance signals; at least one digital to analogue converter (DAC), configured to convert said digital motion artifact estimate into an analogue motion artifact estimate signal; and a feedback loop for sending said analogue motion artifact estimate signal back to an analogue ECG readout module within the readout channel, wherein the analogue ECG readout module is configured to deduct said analogue motion artifact estimate signal from said analogue measured ECG signal.