Patent ID: 8849384

Claim:
A cardiac arrhythmia discrimination system for determining the mechanism of cardiac arrhythmia in a patient, said cardiac arrhythmia discrimination system comprising a catheter and a processor, said system being arranged to measure the impedance of cardiac tissue of the patient at various selected points on the patient's heart during a spontaneously occurring or induced arrhythmia and providing the geometric position of each of said points on the patient's heart, and wherein each of said measurements and positions are arranged to be recorded and analyzed by said processor to determine if a point on the patient's heart exhibits low impedance (Z low ), wherein Z low ≦Z min +0.1(Z max −Z min ), where Z min is the minimum impedance measured and Z max is the maximum impedance measured, said processor being arranged to discard from its impedance measurements any points associated with tissue voltage of less than a minimum voltage or poor contact of the catheter to the cardiac tissue and impedance measurements from mapping points that are too internal to the anatomic shell or points with far-field low amplitude electrograms, and evaluating the remaining points of measured impedance to determine if there is an area of a predetermined size or predetermined percentage of the atrial surface area having plural Z low points therein.