Patent ID: 7410467

Claim:
An active implantable medical device comprising: a plurality of connection terminals able to be connected to electrodes placed in at least three distinct respective sites in a myocardium; means for measuring an intracardiac bio-impedance, comprising means for injecting a current, means for collecting a voltage at selected ones of said plurality of connection terminals, and means able to deliver at an output a dynamic impedance signal that is a function of the injected current and the collected voltage; and means for evaluating an intracardiac volume, said means receiving at an input the impedance signal and delivering at an output a dynamic value of volume representing an instantaneous absolute value of intracardiac volume, said means further comprising means for converting the impedance signal into a volume according to a hyperbolic characteristic in the form Vol=a/(Z+b), wherein Vol is the value of volume delivered by the means for evaluating, Z is the value of the impedance signal received at input, and a and b are constants.