Patent ID: 9549674
Date: 2017-01-24
CPC Classifications: A61B,A61N

Claim:
1. A method for determining a Tei-index of a subject comprising: applying an electric signal to at least a portion of a heart in said subject by two implanted electrodes; measuring a resulting electric signal from at least a portion of said heart collected by two implanted electrodes; determining an impedance signal based on said electric signal and said resulting electric signal; estimating an isovolumetric relaxation time of a heart cycle based on said impedance signal; estimating an isovolumetric contraction time of said heart cycle based on said impedance signal; estimating an election time of said heart cycle based on said impedance signal; determining a Tei-index of said heart based on said estimated isovolumetric relaxation time, said estimated isovolumetric contraction time and said ejection time; calculating a first time derivative of said impedance signal for at least a portion of said heart cycle; and calculating a second time derivative of said impedance signal for at least a portion of said heart cycle, wherein said determining said isovolumetric relaxation time and said isovolumetric contraction time are performed at least partly based on said first and second time derivatives of said impedance signal.