Patent ID: 8170653

Claim:
A cardiac event detection system for detecting a cardiac event in a patient comprising: (a) at least two electrodes for sensing an electrical signal from the patient's heart; (b) an implantable device coupled to said electrodes, said implantable device having an analog-to-digital circuit system contained therein for digitizing said electrical signal to produce a multiplicity of sequential temporally spaced electrical signal segments, each electrical signal segment encompassing a first time period corresponding to a plurality of PQRST waveform signals and being temporally spaced by a second time period from a sequentially adjacent electrical signal segment; (c) a processor contained in said implantable device and electrically coupled to said electrodes, said processor configured to: (i) determine whether an electrical signal segment qualifies as a baseline segment for one of a plurality of discrete temporally spaced time slots based on at least one heart signal parameter criterion; (ii) compute from said plurality of PQRST waveform signals of each electrical signal segment qualifying as a baseline segment, a value of a heart signal parameter therefore and update stored baseline heart signal parameter values for corresponding time slots, (iii) compute said value of said heart signal parameter for said plurality of PQRST waveform signals of an additional electrical signal segment; (iv) generate a statistical measure of said heart signal parameter value based on said baseline heart signal parameter values of a number of said discrete time slots; (v) detect said cardiac event based on a comparison of said statistical measure with said value of said heart signal parameter of said additional electrical signal segment.