Cardiac signal vector selection with monophasic and biphasic shape consideration
First Claim
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1. An implantable cardiac device comprising:
- a plurality of electrodes configured for sensing electrical signals; and
operational circuitry configured for analyzing signals received from the sensing electrodes,wherein the operational circuitry and electrodes are configured to define at least two sensing vectors for sensing cardiac signals and the operational circuitry is configured to perform the following;
for a first sensing vector, calculating each of;
an estimate of signal-to-noise ratio;
an estimate of cardiac signal amplitude; and
a measure of biphasic or monophasic nature of sensed signals; and
combining the signal to noise ratio, cardiac signal amplitude and measure of biphasic or monophasic nature of sensed signals to generate a sensing quality metric for the first sensing vector;
wherein;
the operational circuitry is further configured to sense a plurality of cardiac cycles with selected electrodes for the first vector by applying a detection profile to a sensed cardiac signal to detect a cardiac cycle, wherein the detection profile includes a refractory period and a sensing period, the refractory period being applied to a first portion of the cardiac cycle and the sensing period being applied to at least a second portion of the cardiac cycle; and
the operational circuitry is configured to calculate a measure of biphasic or monophasic nature of cardiac cycles by comparing an average sensed positive amplitude from the first portion of two or more of the cardiac cycles to an average sensed negative amplitude from the first portion of two or more of the cardiac cycles.
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Abstract
Systems, methods and non-transient software media for performing sensing vector selection in an implantable cardiac device by assessing biphasic or monophasic characteristics of the cardiac signal in vectors under analysis. A factor associated with the biphasic or monophasic nature of the cardiac signal, as seen from a given sensing vector, can be inserted into the assessment of which of several available sensing vectors is considered “best” for purposes of cardiac signal analysis. Additional factors may be considered beyond the biphasic or monophasic nature including the quantity of turning points or inflections and amplitude variability.
328 Citations
19 Claims
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1. An implantable cardiac device comprising:
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a plurality of electrodes configured for sensing electrical signals; and operational circuitry configured for analyzing signals received from the sensing electrodes, wherein the operational circuitry and electrodes are configured to define at least two sensing vectors for sensing cardiac signals and the operational circuitry is configured to perform the following; for a first sensing vector, calculating each of; an estimate of signal-to-noise ratio; an estimate of cardiac signal amplitude; and a measure of biphasic or monophasic nature of sensed signals; and combining the signal to noise ratio, cardiac signal amplitude and measure of biphasic or monophasic nature of sensed signals to generate a sensing quality metric for the first sensing vector; wherein; the operational circuitry is further configured to sense a plurality of cardiac cycles with selected electrodes for the first vector by applying a detection profile to a sensed cardiac signal to detect a cardiac cycle, wherein the detection profile includes a refractory period and a sensing period, the refractory period being applied to a first portion of the cardiac cycle and the sensing period being applied to at least a second portion of the cardiac cycle; and the operational circuitry is configured to calculate a measure of biphasic or monophasic nature of cardiac cycles by comparing an average sensed positive amplitude from the first portion of two or more of the cardiac cycles to an average sensed negative amplitude from the first portion of two or more of the cardiac cycles. - View Dependent Claims (4, 5, 6, 7, 8, 9)
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2. An implantable cardiac device comprising:
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a plurality of electrodes configured for sensing electrical signals; and operational circuitry configured for analyzing signals received from the sensing electrodes, wherein the operational circuitry and electrodes are configured to define at least two sensing vectors for sensing cardiac signals and the operational circuitry is configured to perform the following; for a first sensing vector, calculating each of; an estimate of signal-to-noise ratio; an estimate of cardiac signal amplitude; and a measure of biphasic or monophasic nature of sensed signals; and combining the signal to noise ratio, cardiac signal amplitude and measure of biphasic or monophasic nature of sensed signals to generate a sensing quality metric for the first sensing vector; wherein; the operational circuitry is configured to combine the signal to noise ratio, cardiac signal amplitude and measure of biphasic or monophasic nature of cardiac signals to generate a sensing quality metric for the first sensing vector comprises the operational circuitry by finding the sum or product of; a first metric related to the signal to noise ratio; a second metric related to the cardiac signal amplitude; and a third metric related to the measure of biphasic or monophasic nature of cardiac signals. - View Dependent Claims (10, 11, 12, 13, 14, 17, 18, 19)
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3. An implantable cardiac device comprising:
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a plurality of electrodes configured for sensing electrical signals while implanted; and operational circuitry configured for analyzing signals received from the sensing electrodes, wherein the operational circuitry and electrodes are configured to define at least two sensing vectors for sensing cardiac signals and the operational circuitry is configured to perform the following; for a first sensing vector, calculating each of; an estimate of signal-to-noise ratio; an estimate of cardiac signal amplitude; and a measure of biphasic or monophasic nature of sensed signals; and combining the signal to noise ratio, cardiac signal amplitude and measure of biphasic or monophasic nature of sensed signals to generate a sensing quality metric for the first sensing vector; wherein; the operational circuitry is configured to combine the signal to noise ratio, cardiac signal amplitude and measure of biphasic or monophasic nature of cardiac signals to generate a sensing quality metric for the first sensing vector comprises the operational circuitry by calculating a sensing vector score for the first vector using the signal to noise ratio and the cardiac signal amplitude, and adjusting the score in view of the measure of biphasic or monophasic nature of cardiac signals. - View Dependent Claims (15, 16)
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Specification