System and method for indentifying rotors in fractionated signals in persistent atrial fibrillation ablation

A computer-assisted method for quantitative characterizing atrial fibrillation in a patient, comprising:

• recording unipolar atrial fibrillation (AF) signals from multiple sites in a patient's atria using a plurality of probes;
• calculating bipolar electrograms using unipolar AF signals recorded at adjacent sites by an analyzer in connection with the probes, wherein the analyzer includes an analog-to-digital converter;
• extracting an envelope function from the filtered bipolar electrograms using one-dimensional order statistic filtering by the analyzer;
• applying Empirical Mode Decomposition to remove a background from the envelope function of the bipolar electrogram signal to obtain an envelope function of the filtered bipolar electrogram signal;
• applying Hilbert transform to the envelope function of the filtered bipolar electrogram signal to obtain a time series of instantaneous phases of the filtered bipolar electrogram signal;
• displaying a spatial diagram of the instantaneous phases in the patient's atria at one or more times in the time series on a display in connection with the analyzer, wherein the spatial diagram is based on the multiple sites in a patient's atria probed by the plurality of probes;
• highlighting a graphical area in the spatial diagram of the instantaneous phases to show movements of the graphical area on the display;
• demonstrating a rotational movement of the graphical area to show existence of a rotor region in the spatial diagram of the instantaneous phases obtained from the patient's atria, comprising:
• calculating a map of the instantaneous phases in the envelope function of the filtered bipolar electrogram signal in the patient's atria;
• and
• calculating phase shifts at different positions around a center point relative to a phase at the center point, wherein the different positions are at substantially the same distance to the center point;
• identifying the rotor region in the patient's atria if the phase shifts at the different positions rotates around the center point;
• and
• overlaying the rotor region on a map of the patient's atria on the display to locate the rotor region in the patient's atria to allow therapy to be delivered to the located rotor region in the patient's atria, which increases the rate of successful procedural AF terminations.