Patent ID: 8903487

Claim:
An implantable device to detect ischemic events, including: at least one electrode adapted for implantation in a body; circuitry coupled to the electrode to sense signals therefrom and to generate corresponding digital signals; a processor configured to: identify beats in the digital signals associated with a first beat type and a second beat type; analyze the digital signals to collect reference data for the first beat type and the second beat type to determine a first beat baseline and a second beat baseline, wherein the reference data pertains to a first heart signal parameter; measure from the digital signals a plurality of values of the first heart signal parameter for a plurality of beats of the first and second beat types; determine a number of heart signal parameter values existing for the first beat type; determine whether the number of heart signal parameter values for the first beat type is greater than a predetermined threshold value, said predetermined threshold value defining valid reference data; operative when valid reference data exists for the first beat type, apply a first ischemia test that is based at least in part on a comparison of the plurality of values of the first heart signal parameter with said first beat baseline associated with the reference data for the first beat type; and operative when valid reference data does not exist for the first beat type, apply a second ischemia test to the plurality of beats of the first beat type, said second ischemia test being based upon said second beat baseline.