| 摘要 |
A method of and apparatus for determining the physical posture of a patient' s body, having a superior-inferior body, axis, an anteri or posterior body axis and a lateral-medial body axis, in relation to earth's g ravitational field. A medical device having first, secon d and optionally, third DC accelerometers having sensitive axes mounted orthogonal ly within an implantable housing is adapted to be implan ted with the sensitive axes generally aligned with the patient's body axes. Each DC accelerometer generates DC accelerometer signals hav ing characteristic magnitudes and polarities on alignment of the sensitive axis with. against or normal to earth's gravitational field a nd DC accelerometer signals of varying magnitudes and polarities when not so align ed. Body position may be determined through comparison o f the magnitudes and polarities of the DC accelerometer signals with the chara cteristic magnitudes and polarities. A patient activity signal may also be determined from the frequency of body movements recurring over a tim e unit effecting magnitude changes in the DC acceleromet er signals within a certain range of magnitude and frequency. The activity and body position signals may be stored and or used to monit or and effect the delivery of a therapy to the patient, e,g. by controlling the pacing range of a rate responsive pacemaker.
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