Abstract: In a method for enhancing the signal-to-noise ratio of ECG signals, A/D-converted signals from a number of cardiac cycles are time-synchronized to form a signal ensemble, and the correlation between the signals in the ensemble is determined in time intervals, comprising at least two samples, during at least a part of the cardiac cycles. A device for enhancing the signal-to-noise ratio of ECG signals, includes circuitry for recording, A/D-converting and other processing of the ECG signals. A synchronization unit is arranged to time-synchronize the signals from a plurality of cardiac cycles to form a signal ensemble, and a calculator unit controlled by a window unit determines the correlation between the signals in the ensemble in time intervals, comprising at least two samples, during at least a part of the cardiac cycles.

Abstract: In a method and apparatus for processing ECG signals for the purpose of detecting low-amplitude signal structures hidden in noise in the ECG signal, the ECG signals, number of cardiac cycles are analog-to-digital converted, and QRS complexes in the converted signals are detected. The signals from at least two cardiac cycles are cross-correlated, and the correlation between these signals in time intervals which comprise at least the time intervals of the two samples is determined. An output quantity representing the degree of correlation is thus obtained, the magnitude of this quantity designating the amplitude of the signal structure in question. This magnitude can then be analyzed to determine if, and where in the signal, the signal structure arises.