Dynamically filtered beat detection in an implantable cardiac device
First Claim
1. A method of cardiac signal analysis in an implantable cardiac stimulus or monitoring device, the device comprising an implantable canister housing operational circuitry and having a plurality of electrodes coupled to the operational circuitry;
- the method comprising;
capturing a signal from a chosen set of the plurality of electrodes; and
performing cardiac beat detection by comparing a detection threshold to an amplitude of the captured signal by;
a) using a signal that undergoes post-beat filtering for a predefined period of time following the detected cardiac event; and
b) using a signal that undergoes default filtering once the predefined period of time has expired;
wherein the post-beat filtering is configured to attenuate frequencies correlated to T-waves more greatly than the default filtering;
wherein the method is performed on a beat-by-beat basis, such that after detection of a cardiac beat, beat detection using the post-beat filtering is performed and, if no additional beat is detected during the predefined period of time following the detected cardiac event, beat detection using the default filtering is performed.
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Abstract
Methods and implantable devices that detect cardiac events using dynamic filtering. Illustratively, default filtering is performed except for a predefined period of time following detection of cardiac events, during which post-beat filtering is performed instead. The example post-beat filtering applies a narrower pass-band to the signal than the default filtering in order to attenuate T-waves more greatly than the default filtering during a time period after a detected event that is expected to correspond to occurrence of T-waves.
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Citations
20 Claims
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1. A method of cardiac signal analysis in an implantable cardiac stimulus or monitoring device, the device comprising an implantable canister housing operational circuitry and having a plurality of electrodes coupled to the operational circuitry;
- the method comprising;
capturing a signal from a chosen set of the plurality of electrodes; and performing cardiac beat detection by comparing a detection threshold to an amplitude of the captured signal by; a) using a signal that undergoes post-beat filtering for a predefined period of time following the detected cardiac event; and b) using a signal that undergoes default filtering once the predefined period of time has expired; wherein the post-beat filtering is configured to attenuate frequencies correlated to T-waves more greatly than the default filtering; wherein the method is performed on a beat-by-beat basis, such that after detection of a cardiac beat, beat detection using the post-beat filtering is performed and, if no additional beat is detected during the predefined period of time following the detected cardiac event, beat detection using the default filtering is performed. - View Dependent Claims (2, 3, 4, 5, 6)
- the method comprising;
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7. An implantable cardiac stimulus device (ICSD) comprising:
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operational circuitry including a power supply, output capacitor, and microcontroller, the microcontroller controlling operations in the ICSD; and a plurality of electrodes electrically coupled to the operational circuitry to allow sensing of cardiac events;
wherein the operational circuitry is configured to perform the following method;capturing a signal using a selected set of the plurality of electrodes; and performing cardiac beat detection by comparing a detection threshold to an amplitude of the captured signal by; a) using a signal that undergoes post-beat filtering for a predefined period of time following the detected cardiac event; and b) using a signal that undergoes default filtering once the predefined period of time has expired; wherein the post-beat filtering is configured to attenuate frequencies correlated to T-waves more greatly than the default filtering wherein the cardiac beat detection is performed on a beat-by-beat basis, such that after detection of a cardiac beat, beat detection using the post-beat filtering is performed and, if no additional beat is detected during the predefined period of time following the detected cardiac event, beat detection using the default filtering is performed. - View Dependent Claims (8, 9, 10, 11, 12, 13)
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14. An implantable medical device (IMD) comprising:
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operational circuitry, the operational circuitry including a power supply, memory, and a microcontroller, the microcontroller controlling operations in the IMD; and a plurality of electrodes electrically coupled to the operational circuitry to allow sensing of cardiac events;
wherein the operational circuitry is configured to perform the following method;capturing a signal using a selected set of the plurality of electrodes; and detecting cardiac events by comparing a detection threshold to an amplitude of the captured signal by; a) using a signal that undergoes post-beat filtering for a predefined period of time following the detected cardiac event; and b) using a signal that undergoes default filtering once the predefined period of time has expired; wherein the post-beat filtering is configured to attenuate frequencies correlated to T-waves more greatly than the default filtering wherein the detecting cardiac events is performed on a beat-by-beat basis, such that after detection of a cardiac beat, beat detection using the post-beat filtering is performed and, if no additional beat is detected during the predefined period of time following the detected cardiac event, beat detection using the default filtering is performed. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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Specification