Trending of systolic murmur intensity for monitoring cardiac disease with implantable device
First Claim
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1. An implantable cardiac device, comprising:
- a pressure sensor adapted for disposition so as to sense the acoustic vibrations produced by a systolic murmur and produce a pressure signal reflective thereof;
circuitry for measuring the intensity of the systolic murmur from the pressure signal produced by the pressure sensor;
an impedance sensor configured to measure transthoracic impedance reflective of cardiac volume;
a controller programmed to record a baseline murmur intensity; and
,wherein the controller is further programmed to measure a current murmur intensity as an average of intensity measurements taken over some period of time, compare the current murmur intensity to the baseline murmur intensity, and detect a change indicative of worsening cardiac status if the current murmur intensity exceeds the baseline murmur intensity by a first specified threshold amount and if the transthoracic impedance measurement indicates an increase in cardiac volume above a second specified threshold amount.
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Abstract
Described is an implantable device configured to monitor for changes in the intensity and/or duration of a systolic murmur such as mitral regurgitation by means of an acoustic sensor. Such changes may be taken to indicate a change in a patient'"'"'s heart failure status. Upon detection of a worsening in the patient'"'"'s heart failure statue, the device may be programmed to alert clinical personnel over a patient management network and/or make appropriate adjustments to pacing therapy.
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Citations
20 Claims
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1. An implantable cardiac device, comprising:
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a pressure sensor adapted for disposition so as to sense the acoustic vibrations produced by a systolic murmur and produce a pressure signal reflective thereof; circuitry for measuring the intensity of the systolic murmur from the pressure signal produced by the pressure sensor; an impedance sensor configured to measure transthoracic impedance reflective of cardiac volume; a controller programmed to record a baseline murmur intensity; and
,wherein the controller is further programmed to measure a current murmur intensity as an average of intensity measurements taken over some period of time, compare the current murmur intensity to the baseline murmur intensity, and detect a change indicative of worsening cardiac status if the current murmur intensity exceeds the baseline murmur intensity by a first specified threshold amount and if the transthoracic impedance measurement indicates an increase in cardiac volume above a second specified threshold amount. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method, comprising:
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producing a pressure signal reflective of the acoustic vibrations produced by a systolic murmur; filtering the pressure signal; measuring a parameter related to the signal energy of the filtered pressure signal to represent the murmur intensity; recording a baseline murmur intensity; measuring transthoracic impedance reflective of cardiac volume; and
,measuring a current murmur intensity as an average of intensity measurements taken over some period of time, comparing the current murmur intensity to the baseline murmur intensity, and. detecting a change indicative of worsening cardiac status if the current murmur intensity exceeds the baseline murmur intensity by a first specified threshold amount and if the transthoracic impedance measurement indicates an increase in cardiac volume above a second specified threshold amount. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification