Abstract: Disclosed is a system and a method for computer-supported analysis of arrhythmic potentials in ECG signals, particularly those of late potentials. Interference discrimination advantages of frequency domain analysis are combined with temporal localization advantages of time domain analysis to determine the accurate location of arrhythmic potentials. Several small signal segments are selected in an ECG waveform. A determination is made of parameters corresponding to extended signals which closely match fluctuations of each respective small signal, allowing more information is discerned about the small signals than is possible with more conventional techniques. A comparison is made with respect to extended signals rather than small signals. Two autoregressive models are used, the maximum entropy method and adaptive filter determination. Area integrals of the frequency characteristics of small signal segments are recorded successively with respect to the frequency range of the arrhythmic potentials analyzed.