A system of determining regions of interest for cardiac ablation using fractionation, comprising: a plurality of sensors , each configured to detect one of a plurality of electro-cardiogram (ECG) signals over time, each ECG signal indicating electrical activity of a heart; a processing device comprising one or more processor configured to: determine, for each of the plurality of ECG signals, one or more local activation times (LATs) each indicating a time of activation of a corresponding ECG signal; generate, based on the determined one or more LATs of each of the plurality of ECG signals, one or more driver maps and one or more perpetuator maps , each representing the electrical activity of the heart; derive parameters from the driver and perpetuator maps , using at least fractionation, wherein deriving the parameters comprises: filtering the LATs and removing non-fractionated LATs comprising non-fractionated single , short double and long double potentials; finding windows of fractionation using the filtered LATs; and producing fractionated ECGs using the windows of fractionation; process and combine the derived parameters into driver evidence and perpetuator evidence; and determine the regions of interest for cardiac ablation in accordance with the fractionation used to derive the driver evidence and the perpetuator evidence; and a display device . a plurality of sensors , each configured to detect one of a plurality of electro-cardiogram (ECG) signals over time, each ECG signal indicating electrical activity of a heart; a processing device comprising one or more processor configured to: determine, for each of the plurality of ECG signals, one or more local activation times (LATs) each indicating a time of activation of a corresponding ECG signal; generate, based on the determined one or more LATs of each of the plurality of ECG signals, one or more driver maps and one or more perpetuator maps , each representing the electrical activity of the heart; derive parameters from the driver and perpetuator maps , using at least fractionation, wherein deriving the parameters comprises: filtering the LATs and removing non-fractionated LATs comprising non-fractionated single , short double and long double potentials; finding windows of fractionation using the filtered LATs; and producing fractionated ECGs using the windows of fractionation; process and combine the derived parameters into driver evidence and perpetuator evidence; and determine the regions of interest for cardiac ablation in accordance with the fractionation used to derive the driver evidence and the perpetuator evidence; and a display device . determine, for each of the plurality of ECG signals, one or more local activation times (LATs) each indicating a time of activation of a corresponding ECG signal; generate, based on the determined one or more LATs of each of the plurality of ECG signals, one or more driver maps and one or more perpetuator maps , each representing the electrical activity of the heart; derive parameters from the driver and perpetuator maps , using at least fractionation, wherein deriving the parameters comprises: filtering the LATs and removing non-fractionated LATs comprising non-fractionated single , short double and long double potentials; finding windows of fractionation using the filtered LATs; and producing fractionated ECGs using the windows of fractionation; filtering the LATs and removing non-fractionated LATs comprising non-fractionated single , short double and long double potentials; finding windows of fractionation using the filtered LATs; and producing fractionated ECGs using the windows of fractionation; process and combine the derived parameters into driver evidence and perpetuator evidence; and determine the regions of interest for cardiac ablation in accordance with the fractionation used to derive the driver evidence and the perpetuator evidence; and a display device . <EOS>