Patent ID: 8204585

Claim:
A signal separation method performed at least in part in an implantable device, the method comprising: coupling a plurality of implantable electrodes to the implantable device to allow concurrent measurement of bio-impedance across multiple vectors, including intracardiac, trans-cardiac, and trans-thoracic vectors; measuring a plurality of impedance signals concurrently across the multiple vectors using the plurality of implantable electrodes, the plurality of impedance signals comprising a primary impedance signal that includes a respiratory component and noise comprising a cardiac stroke component that corrupts the respiratory component due to an overlap in heart and respiratory rates or an unstable heart rate; and separating a respiration signal from the plurality of impedance signals including the cardiac stroke component using a signal separation technique on a combination of the plurality of impedance signals, the separated respiration signal characterized by the primary impedance signal substantially free of the corrupting cardiac stroke component; and providing a system output based on the respiration signal.