Patent ID: 9241653
Filing Date: 2016-01-26
CPC Classification: A61B,A61N

Claim Text:
1. An implantable medical device comprising: multiple electrodes configured to pace and sense at least a portion of a heart; an electrode input electrically connectable to said multiple electrodes of which at least one is provided on a cardiac lead connectable to said implantable medical device; a signal generator electrically connected to said electrode input and configured to generate an electric signal to be applied to at least a portion of the heart in a subject by two electrodes of said multiple electrodes; an impedance processor electrically connected to said electrode input and said signal generator and configured to determine an impedance signal based on said generated electric signal and a resulting electric signal collected by said two electrodes of said multiple electrodes; an isovolumetric contraction time processor configured to estimate an isovolumetric contraction time of a heart cycle based on said impedance signal; an isovolumetric relaxation time processor configured to estimate an isovolumetric relaxation time of said heart cycle based on said impedance signal; an ejection time processor configured to estimate an ejection time of said heart cycle based on said impedance signal; wherein said isovolumetric contraction time, said isovolumetric relaxation time, and said ejection time are based on said impedance signal for one and said same heart cycle; an index processor configured to determine a Tei-index of said heart based on said estimated isovolumetric relaxation time, said estimated isovolumetric contraction time and said ejection time; a pacing signal generator connected to said electrode input and configured to generate therapy pacing signals according to a cardiac therapy scheme, said therapy pacing signals being applicable to at least a portion of said heart by two electrodes of said multiple; and a cardiac therapy controller connected to said index processor and said pacing signal generator and configured to adjust said cardiac therapy scheme based on said Tei-index; wherein said impedance processor comprises: a first derivative generator configured to calculate a first time derivative of said impedance signal for at least a portion of said heart cycle; and a second derivative generator configured to calculate a second time derivative of said impedance signal for at least a portion of said heart cycle, and wherein said isovolumetric contraction time processor and said isovolumetric relaxation time processor are configured to estimate said isovolumetric contraction time and said isovolumetric relaxation time, respectively, at least partly based on said first time derivative and said second time derivative of said impedance signal.