Selection of optimal accelerometer sensing axis for rate response in leadless pacemaker
First Claim
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1. A method for automatically monitoring a patient by an implantable medical device, comprising:
- receiving signals from each real axis of a multi-axis sensor by a processor of the implantable medical device;
generating from the real axis signals a virtual signal for each of a plurality of virtual axes of the multi-axis sensor;
determining a first value of an activity metric during a first activity state of the patient for each of the real axis signals and each of the virtual signals;
determining a second value of the activity metric during a second activity state of the patient for each of the real axis signals and each of the virtual signals;
identifying by the processor an optimal signal axis from the real axes and the plurality of virtual axes for monitoring a physiological signal of the patient by identifying one of the real axis signals and the virtual signals having at least one of a lowest variation of the first value of the activity metric during the first activity state and a greatest difference between the first value and the second value of the activity metric;
storing a set of coordinates defining the optimal axis as respective weighting factors of the signals received from each real axis of the multi-axis sensor;
monitoring the physiological signal of the patient by determining a third value of the activity metric using the multi-axis sensor signals and the stored weighting factors; and
controlling a rate of delivering a therapy to the patient by a signal generator of the implantable medical device based on the third value of the activity metric.
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Abstract
A medical device and associated method record signals from each real axis of a multi-axis sensor. An optimal axis for monitoring a physiological signal of the patient is identified from the real axes of the multi-axis sensor and multiple virtual axes. Coordinates defining the optimal axis are stored as respective weighting factors of the signals from each real axis of the multi-axis sensor. A metric of the physiological signal is determined using the multi-axis sensor signals and the weighting factors.
116 Citations
21 Claims
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1. A method for automatically monitoring a patient by an implantable medical device, comprising:
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receiving signals from each real axis of a multi-axis sensor by a processor of the implantable medical device; generating from the real axis signals a virtual signal for each of a plurality of virtual axes of the multi-axis sensor; determining a first value of an activity metric during a first activity state of the patient for each of the real axis signals and each of the virtual signals; determining a second value of the activity metric during a second activity state of the patient for each of the real axis signals and each of the virtual signals; identifying by the processor an optimal signal axis from the real axes and the plurality of virtual axes for monitoring a physiological signal of the patient by identifying one of the real axis signals and the virtual signals having at least one of a lowest variation of the first value of the activity metric during the first activity state and a greatest difference between the first value and the second value of the activity metric; storing a set of coordinates defining the optimal axis as respective weighting factors of the signals received from each real axis of the multi-axis sensor; monitoring the physiological signal of the patient by determining a third value of the activity metric using the multi-axis sensor signals and the stored weighting factors; and controlling a rate of delivering a therapy to the patient by a signal generator of the implantable medical device based on the third value of the activity metric. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. An implantable medical device, comprising:
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a multi-axis sensor having at least two real axes; a therapy delivery module comprising a signal generator; and a processor configured to; receive signals from each real axis of the multi-axis sensor; generate from the real axis signals a virtual signal for each of a plurality of virtual axes of the multi-axis sensor; determine a first value of an activity metric during a first activity state of the patient for each of the real axis signals and each of the virtual signals; determine a second value of the activity metric during a second activity state of the patient for each of the real axis signals and each of the virtual signals; identify an optimal axis from the real axes and the plurality of virtual axes for monitoring a physiological signal of the patient by identifying one of the real axis signals and the virtual signals having at least one of a lowest variation of the first value of the activity metric during the first activity state and a greatest difference between the first value and the second value of the activity metric; store coordinates defining the optimal axis as respective weighting factors of the signals from each axis of the multi-axis sensor; determine a third value of the activity metric of the physiological signal of the patient using the multi-axis sensor signals and the weighting factors; and control a rate of delivering a therapy to the patient by the signal generator based on the third value of the activity metric. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A non-transitory computer readable storage medium storing a set of instructions that cause a processor of an implantable medical device comprising a multi-axis sensor to:
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receive signals from each real axis of the multi-axis sensor; generate from the real axis signals a virtual signal for each of a plurality of virtual axes of the multi-axis sensor; determine a first value of an activity metric during a first activity state of the patient for each of the real axis signals and each of the virtual signals; determine a second value of the activity metric during a second activity state of the patient for each of the real axis signals and each of the virtual signals; identify an optimal axis for monitoring a physiological signal of the patient from the real axes of the multi-axis sensor and the plurality of virtual axes by identifying one of the real axis signals and the virtual signals having at least one of a lowest variation of the first value of the activity metric during the first activity state and a greatest difference between the first value and the second value of the activity metric; store coordinates defining the optimal axis as respective weighting factors of the signals from each real axis of the multi-axis sensor; determine a third value of the activity metric of the physiological signal using the multi-axis sensor signals and the weighting factors; and control a rate of delivering a therapy to the patient by a signal generator of the implantable medical device based on the third value of the activity metric.
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Specification