Measurement of cardiac cycle length and pressure metrics from pulmonary arterial pressure
First Claim
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1. A method of monitoring a cardiovascular pressure signal in a medical device, comprising:
- identifying, by a medical device, a plurality of fiducial points within a first derivative signal of a cardiovascular pressure signal without reference to cardiovascular electrical activity; and
identifying, by the medical device, a length of time between consecutive ones of the fiducial points as a cardiac cycle length,wherein identifying the plurality of fiducial points comprises;
comparing the first derivative signal to a threshold;
identifying a point within the first derivative signal that satisfies the threshold;
identifying the fiducial point within the first derivative signal subsequent to the point within the first derivative signal that satisfies the threshold; and
initiating a blanking period that begins at the identified point that satisfies the threshold, andwherein comparing the first derivative signal to the threshold comprises not comparing the first derivative signal to the threshold for identification of a subsequent one of the fiducial points during the blanking period, wherein identifying the plurality of fiducial points further comprises initiating, by the medical device, a time window from the identified point within the first derivative signal that satisfies the threshold, the time window extending forward in time, andwherein identifying the fiducial point within the first derivative signal subsequent to the point within the derivative signal that satisfies the threshold comprises identifying, within the time window, a point of maximum slope within the first derivative signal subsequent to the point within the first derivative signal that satisfies the threshold.
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Abstract
Various techniques for measuring cardiac cycle length and pressure metrics based on pulmonary artery pressures are described. One example method described includes identifying a point within a derivative signal of a cardiovascular pressure signal without reference to electrical activity of a heart, initiating a time window from the identified point in the derivative signal, identifying a point within the cardiovascular signal within the time window, and determining at least one of a systolic pressure or diastolic pressure based on the identified point.
19 Citations
20 Claims
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1. A method of monitoring a cardiovascular pressure signal in a medical device, comprising:
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identifying, by a medical device, a plurality of fiducial points within a first derivative signal of a cardiovascular pressure signal without reference to cardiovascular electrical activity; and identifying, by the medical device, a length of time between consecutive ones of the fiducial points as a cardiac cycle length, wherein identifying the plurality of fiducial points comprises; comparing the first derivative signal to a threshold; identifying a point within the first derivative signal that satisfies the threshold; identifying the fiducial point within the first derivative signal subsequent to the point within the first derivative signal that satisfies the threshold; and initiating a blanking period that begins at the identified point that satisfies the threshold, and wherein comparing the first derivative signal to the threshold comprises not comparing the first derivative signal to the threshold for identification of a subsequent one of the fiducial points during the blanking period, wherein identifying the plurality of fiducial points further comprises initiating, by the medical device, a time window from the identified point within the first derivative signal that satisfies the threshold, the time window extending forward in time, and wherein identifying the fiducial point within the first derivative signal subsequent to the point within the derivative signal that satisfies the threshold comprises identifying, within the time window, a point of maximum slope within the first derivative signal subsequent to the point within the first derivative signal that satisfies the threshold. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A medical device system for monitoring a cardiovascular pressure signal, comprising:
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at least one pressure sensor to generate a cardiovascular pressure signal; and at least one pressure analysis module configured to; identify a plurality of fiducial points within a first derivative signal of a cardiovascular pressure signal without reference to electrical activity; and identify a length of time between consecutive ones of the fiducial points as a cardiac cycle length, wherein the at least one pressure analysis module configured to identify the plurality of fiducial points is further configured to; compare the first derivative signal to a threshold; identify a point within the first derivative signal that satisfies the threshold; identify the fiducial point within the first derivative signal subsequent to the point within the first derivative signal that satisfies the threshold; and initiate a blanking period that begins at the identified point that satisfies the threshold, and wherein at least one pressure analysis module configured to compare the first derivative signal to the threshold is configured to not compare the first derivative signal to the threshold for identification of a subsequent one of the fiducial points during the blanking period, wherein the at least one pressure analysis module configured to identify the plurality of fiducial points further is further configured to initiate a time window from the identified point within the derivative signal that satisfies the threshold, the time window extending forward in time, and wherein the at least one pressure analysis module configured to identify the fiducial point within the first derivative signal subsequent to the point within the first derivative signal that satisfies the threshold is configured to identify, within the time window, a point of maximum slope within the first derivative signal subsequent to the point within the first derivative signal that satisfies the threshold. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. A computer-readable storage medium comprising instructions that, when executed, cause a cardiovascular pressure analysis module to:
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identify a plurality of fiducial points within a first derivative signal of a cardiovascular pressure signal without reference to cardiovascular electrical activity; and identify a length of time between consecutive ones of the fiducial points as a cardiac cycle length, wherein the instructions that, when executed, cause a pressure analysis module to identify the plurality of fiducial points comprise instructions that, when executed, cause the pressure analysis module to; compare the first derivative signal to a threshold; identify a point within the first derivative signal that satisfies the threshold; identify the fiducial point within the first derivative signal subsequent to the point within the first derivative signal that satisfies the threshold; and initiate a blanking period that begins at the identified point that satisfies the threshold, and wherein the instructions that, when executed, cause a pressure analysis module to compare the first derivative signal to the threshold comprise instructions that, when executed, cause the pressure analysis module to not compare the first derivative signal to the threshold for identification of a subsequent one of the fiducial points during the blanking period, wherein the instructions that, when executed, cause a pressure analysis module to identify the plurality of fiducial points further comprise instructions that, when executed, cause the pressure analysis module to initiate a time window from the identified point within the first derivative signal that satisfies the threshold, the time window extending forward in time, and wherein the instructions that, when executed, cause a pressure analysis module to identify the fiducial point within the first derivative signal subsequent to the point within the first derivative signal that satisfies the threshold comprise instructions that, when executed, cause the pressure analysis module to identify, within the time window, a point of maximum slope within the first derivative signal subsequent to the point within the first derivative signal that satisfies the threshold. - View Dependent Claims (18, 19, 20)
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Specification