A device that monitors and evaluates electrogram signals representing electric activities of a heart chamber, and includes a signal input connected to a mapping catheter, and a signal processing and evaluation unit. The mapping catheter includes one or more electrode poles that pick up electric potentials and generate electrogram signals therefrom. When an electrogram signal is received by the signal input, the signal processing and evaluation unit identifies waveform deflections in the electrogram signal, measures deflection intervals between each pair of consecutive deflection complexes in the electrogram signal, measures at least one metric that characterizes a morphology of a deflection complex in the electrogram signal, generates a multi-dimensional deflection vector of at least two dimensions for each identified deflection, determines a distance between each pair of consecutive deflections from the multi-dimensional deflection vectors, and determines a cumulative distance between deflections in a time window of predetermined length.
