Patent ID: 6129743
Filing Date: 2000-10-10
Classification: A61N

Abstract:
A method for defibrillating a patient's heart with a defibrillator, comprising the steps of:detecting and storing a fibrillation waveform recorded for the patient;charging a high voltage capacitor in the defibrillator;obtaining a sample of waveform parameters during said charging step, said waveform parameters including;(1) a maximum value of a calculated first moving rectified average, said first average based on values of said fibrillation waveform within a window of a first predetermined length of time,(2) a maximum value of a calculated second moving rectified average, said second average based on values of said fibrillation waveform within a window of a second predetermined length of time longer than said first predetermined length of time, and(3) a ratio of said first average and said second average;determining a set of threshold values for each waveform parameter based on the sample;continuously calculating said first and second averages and said ratio;comparing said second average calculated in said calculating step to a first one of the threshold values;comparing said ratio calculated in said calculating step to a second one of the threshold value; andafter completion of the charging step, delivering a defibrillation shock to the patient's heart during a period of fibrillation when said second average and said ratio exceed the first and second threshold values, respectively.