A method of enhancing the signal-to-noise ratio (SNR) of measured electrocardiogram (ECG) signals is provided. The method includes the steps of providing at least three cardiac input signals derived from the measured ECG signals S1 and forming a first estimate U1 S2 from each of at least three pairs of input signals. Moreover, the method includes the steps of forming a second estimate U2 S3 from each of at least three input signals; comparing S4 the polarity and the amplitude of a first and second estimate U1, U2 to at least one threshold T; generating S5 a composite signal X, wherein the polarity and the amplitude of the composite signal X depend on the result of the comparison; and using S6 the generated composite signal X to produce an output signal with enhanced signal-to-noise ratio (SNR). Furthermore, a corresponding cardiac device is also provided.