Patent ID: 8041416

Claim:
A method of assessing a patient's susceptibility to ventricular arrhythmia, comprising: obtaining data by applying electrodes to the patient, the electrodes being adapted to detect electrocardiographic signals from the patient; selectively delivering a plurality of subthreshold electrical stimuli into the patient's body that are synchronized to a plurality of selected cardiac cycles to present stimulated cardiac cycles to the electrodes such that other unselected cardiac cycles are unstimulated to present unstimulated reference cardiac cycles to the electrodes; using the electrodes to record a plurality of the electrocardiographic signals including the stimulated cardiac cycles and the unstimulated reference cardiac cycles; analyzing the plurality of electrocardiographic signals that are recorded by creating a matrix of vectorized time-phase data representing a plurality cardiac cycles contained in the electrocardiographic signals that are recorded; processing the matrix to generate spectral analytic representation of the matrix; analyzing at least the spectral analytic representation to determine at least one alternans index for the patient; and displaying the at least one alternans index as an indicator of the patient's susceptibility to arrhythmia.