A method, system, apparatus and device for processing an ECG signal to remove or reduce noise from the ECG signal attributable to EMG and/or motion artifacts. The novel algorithm common to all aspects of the device can include wavelet decomposing an ECG signal to produce a set of approximation coefficients and a plurality of sets of detail coefficients, locally fitting subsets of the set of approximation coefficients to second order polynomials, adjusting the set of approximation coefficients by the locally fitted second order polynomials, setting some of the detail coefficients to zero, and reconstructing an ECG signal with reduced noise based on the modified set of approximation coefficients and the modified plurality of sets of detail coefficients.
