The disclosure relates to a method for determining a plurality of action potentials in the heart having the following steps:a) Recording a surface ECG signal synchronously with at least 64 channels,b) Recording at least one IEGM signal,c) Processing the surface ECG signal by means of ICA analysis and determining the sum and position of a plurality of action potentials in the heart based on the ICA analysis, and,d) Comparing the at least one IEGM signal to the plurality of action potentials and correcting the sum and/or position of at least one of the plurality of action potentials in the heart based on this comparison.The disclosure further relates to a corresponding device, a corresponding computer program product, and a corresponding system.
