The present invention relates to an implantable cardioverter-defibrillator or pacemaker whose standard circuitry is used to trend a physiological cardiac parameter using intra-cardiac impedance measurements. The trend information may be used to predict the onset of a sudden cardiac death (SCD) event....http://www.google.de/patents/US7826891?utm_source=gb-gplus-sharePatent US7826891 - Method and apparatus for trending a physiological cardiac parameter
