Patent ID: 8082028

Claim:
A method for classifying of supraventricular tachyarrhythmia or SVT from ventricular tachyarrhythmia or VT using signals provided by an electrogram comprising: providing a template signal x(i) and a test signal y(i), wherein the template signal and the test signal comprise samples from an electrogram; defining subspaces associated with said template signal wherein R denotes a signal space that spans from V min to V max , where V min is a minimum amplitude and V max is a maximum amplitude and R is divided into subspaces R P , R Z , and R N such that R=R P ∪R Z ∪R N and R P ∩R Z =R P ∩R N =R Z ∩R N =Ø, where ∪ is a union operator, ∩ is an intersection operator, and Ø represents null space; transforming at least the test signal into a representation of the test signal ty(i) based on a trichotomization function: ty ⁡ ( i ) = { 1 if ⁢ ⁢ y ⁡ ( i ) ∈ R P 0 if ⁢ ⁢ y ⁡ ( i ) ∈ R Z - 1 if ⁢ ⁢ y ⁡ ( i ) ∈ R N wherein ty(i) are integer values; determining a correlation between the template signal and the test signal by summing the representation of the test signal ty(i): ∑ i = 1 L ⁢ ⁢ ty ⁡ ( i ) wherein L represents a number of said samples; and, classifying of SVT from VT based on the correlation, performed using an implantable cardiac device.