Ischemia detection using a heart sound sensor
First Claim
1. A method comprising:
- sensing a heart sound signal using a medical device, the heart sound associated with mechanical vibration of a heart of a patient;
establishing a baseline value of a characteristic of at least one of an S3 or S4 heart sound in the heart sound signal;
sensing at least one subsequent heart sound signal for the patient using the device;
deeming that an ischemic event occurred using at least a measured subsequent change in the heart sound characteristic from the established baseline value of the characteristic;
discriminating a transient ischemic event from an acute myocardial infarction (AMI) using the measured subsequent change in the heart sound characteristic from the established baseline value of the heart sound characteristic; and
providing an indication of the ischemic event or AMI to a user or process.
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Abstract
A system comprising an implantable medical device (IMD) includes an implantable heart sound sensor to produce an electrical signal representative of at least one heart sound. The heart sound is associated with mechanical activity of a patient'"'"'s heart. Additionally, the IMD includes a heart sound sensor interface circuit coupled to the heart sound sensor to produce a heart sound signal, and a signal analyzer circuit coupled to the heart sound sensor interface circuit. The signal analyzer circuit measures a baseline heart sound signal, and deems that an ischemic event has occurred using, among other things, a measured subsequent change in the heart sound signal from the established baseline heart sound signal.
482 Citations
19 Claims
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1. A method comprising:
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sensing a heart sound signal using a medical device, the heart sound associated with mechanical vibration of a heart of a patient; establishing a baseline value of a characteristic of at least one of an S3 or S4 heart sound in the heart sound signal; sensing at least one subsequent heart sound signal for the patient using the device; deeming that an ischemic event occurred using at least a measured subsequent change in the heart sound characteristic from the established baseline value of the characteristic; discriminating a transient ischemic event from an acute myocardial infarction (AMI) using the measured subsequent change in the heart sound characteristic from the established baseline value of the heart sound characteristic; and providing an indication of the ischemic event or AMI to a user or process. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A method comprising:
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sensing a heart sound signal using a medical device, the heart sound associated with mechanical vibration of a heart of a patient; establishing a baseline value of a characteristic of at least one of an S3 or S4 heart sound in the heart sound signal; sensing at least one subsequent heart sound signal for the patient using the device; deeming that an ischemic event occurred at least in part using a measured change in the heart sound characteristic from the baseline value of the heart sound characteristic when a time constant of the change has a range of several seconds to several minutes; determining a heart failure condition of a patient using the measured change in the heart sound signal from the baseline heart sound signal when the time constant has a range of several hours to several days; providing an indication of the ischemic event or heart failure condition to a user or process. - View Dependent Claims (18)
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19. A method comprising:
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sensing a heart sound signal using a medical device, the heart sound associated with mechanical vibration of a heart of a patient; establishing a baseline value of a characteristic of at least one of an S3 or S4 heart sound in the heart sound signal; sensing at least one subsequent heart sound signal for the patient using the device; measuring the heart sound in association with a sensed electrical cardiac activity signal; assigning a first weight to the measured subsequent change in the heart sound from the established baseline value of the heart sound characteristic and a second weight to a measured change in the electrical cardiac signal from an established baseline electrical cardiac signal; and deeming an ischemic event occurred using at least a measured change in the value of the heart sound characteristic from the established baseline value of the characteristic, the measured change in the electrical cardiac signal, and the assigned weights; and providing an indication of the ischemic event to a user or process.
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Specification