초록 ▼

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 DC accele

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 DC accelerometers having sensitive axes mounted orthogonally within an implantable housing is adapted to be implanted with the sensitive axes generally aligned with the patient\s body axes. Each DC 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. Body position may be determined through comparison of the magnitudes and polarities of the DC accelerometer signals with the characteristic magnitudes and polarities. A patient activity signal may also be determined from the frequency of body movements recurring over a time unit effecting magnitude changes in the DC accelerometer signals within a certain range of magnitude and frequency. The activity and body position signals may be stored and/or used to monitor and effect the delivery of a therapy to the patient, e.g. by controlling the pacing rate of a rate responsive pacemaker.

대표청구항 ▼

A method of 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 comprising the steps of: implanting a multi-axis, solid state sensor, comprising first an

A method of 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 comprising the steps of: implanting a multi-axis, solid state sensor, comprising first and second DC accelerometers having first and second sensitive axes, respectively, which respond to earth\s gravitational field to provide first and second respective DC accelerometer signals of a magnitude and polarity dependent on the degree of alignment therewith, in the patient\s body so that said first and second sensitive axes are generally aligned with a respective first and second one of said superior-inferior, anterior-posterior or lateral-medial body axes; defining a first characteristic magnitude and polarity of said first and second DC accelerometer signals on alignment of the sensitive axes of said first and second DC accelerometers with earth\s gravitational field, a second characteristic magnitude and polarity of said first and second DC accelerometer signals on alignment against earth\s gravitational field, and a third characteristic magnitude and polarity of said first and second DC accelerometer signals on alignment normal to earth\s gravitational field; deriving first and second DC accelerometer signals from said first and second DC accelerometers as the patient assumes various body positions moving said first or second sensitive axes generally into alignment with earth\s gravitational field; and determining the body posture of the patient through comparison of the magnitudes and polarities of said derived first and second DC accelerometer signals with the magnitudes and polarities of said first, second and third characteristic magnitudes and polarities.