Patent ID: 7953487

Claim:
An implantable heart stimulating device comprising: an activity sensor configured to interact in vivo with a living subject to detect physical activity of the subject and to generate and emit an activity signal indicative of said activity; a blood temperature sensor configured to interact in vivo with the subject to measure blood temperature inside the heart of the subject and to generate and emit a temperature signal indicative of the measured blood temperature; and a processor connected to said activity sensor and to said blood temperature sensor that receives said activity signal and said temperature signal therefrom, respectively, and said processor, from said activity signal, being configured to detect at least two onsets of activity by the subject and, for each of said at least two onsets of activity, to correlate a magnitude of a characteristic dip in the measured blood temperature represented in said temperature signal with a corresponding activity level, to thereby obtain at least two respective correlation points and, from said at least two correlation points, to generate an indicator value representing a degree of congestive heart failure of the subject, and to make said indicator value available as an output of the processor.