Abstract: The present invention provides a method and apparatus for detecting and treating sleep respiratory events that includes a plurality of sensors gathering physiological data related to sleep respiratory events. A processor extracts an average cycle length and a frequency of at least one of Cheyne-Stokes respiration and periodic breathing based upon the physiological data, and determines whether therapy is required based on the average cycle length and the frequency.

Abstract: A method of and apparatus for determining the physical posture of a patient's body, having a superior-inferior body axis, an anterior-posterior body axis and a lateral-medial body axis, in relation to earth's gravitational field. A medical device having first, second and, optionally, third accelerometers having sensitive axes mounted orthogonally within an implantable housing is adapted to be implanted with the sensitive axes nominally aligned with ideal X, Y and Z device axes correlated to patient body axes. Each accelerometer generates DC accelerometer signals having characteristic magnitudes and polarities on alignment of the sensitive axis with, against or normal to earth's gravitational field and DC accelerometer signals of varying magnitudes and polarities when not so aligned. The actual pitch and roll angles of the sensitive axes of the accelerometers in the implanted IMD with respect to the true gravitational axes are determined and the yaw angles are determined or estimated.

Abstract: A method and apparatus for discriminating between stable and unstable ventricular tachycardias based on a measurement of oxygen saturation. Reference values for average oxygen saturation level and of the pulsatile characteristic of the oxygen saturation level are taken while a patient is in a resting condition. Measurements of oxygen saturation are also taken in response to the detection of a high heart rate, and are compared to the reference measurements to discriminate between stable and unstable ventricular tachyarrhythmias. An unstable tachyarrhythmia is diagnosed if a tachycardia is diagnosed and the current oxygen saturation level is similar to the reference average oxygen saturation level or if the oxygen saturation as presently measured displays a decreased pulsatile characteristic as compared to the reference measurements.