Method and system to detect R-waves in cardiac activity signals

Patent metadata

Field	Value
Publication number	US-11547339-B2
Application number	US-202017060361-A
Country	US
Kind code	B2
Filing date	Oct 1, 2020
Priority date	Jun 13, 2018
Publication date	Jan 10, 2023
Grant date	Jan 10, 2023

Abstract

A computer implemented method and system for detecting arrhythmias in cardiac activity are provided. The method is under control of one or more processors configured with specific executable instructions. The method obtains far field cardiac activity (CA) signals and applies a direction related responsiveness (DRR) filter to the CA signals to produce DRR filtered signals. The method compares a current sample from the CA signals to a prior sample from the DRR filtered signals to identify a direction characteristic of the CA signals and defines the DRR filter based on a timing constant that is set based on the direction characteristic identified. The method analyzes the CA signals in connection with the DRR filtered signals to identify a peak characteristic of the CA signals and determines peak to peak intervals between successive peak characteristic. The method detects at least one of noise or an arrhythmia based on the peak to peak intervals and records results of the detecting.

First claim

What is claimed is:

1. A computer implemented method for detecting arrhythmias in cardiac activity, comprising:
under control of one or more processors configured with specific executable instructions,
obtaining far field cardiac activity (CA) signals;
applying a direction related responsiveness (DRR) filter to the CA signals to produce DRR filtered signals;
comparing a current sample from the CA signals to a prior sample from the DRR filtered signals to identify a first characteristic of the CA signals;
defining the DRR filter based on the first characteristic identified;
analyzing the CA signals in connection with the DRR filtered signals to identify a second characteristic of the CA signals;
detecting at least one of noise or an arrhythmia based on the second characteristic; and
recording results of the detecting.

2. The method of claim 1 , further comprising setting a parameter of the DRR filter to a first value when the first characteristic indicates an increasing trend in the CA signals and setting the parameter of the DRR filter to a second value when the first characteristic indicates a decreasing trend in the CA signals.

3. The method of claim 2 , wherein the first value represents a time constant that is shorter than the second value.

4. The method of claim 2 , wherein the first value is used by the DRR filter to produce the DRR filtered signals that respond to the decreasing trend in the CA signals more slowly as compared to a responsiveness of the DRR filter when set to the second value in response to the increasing trend in the CA signals.

5. The method of claim 1 , wherein the analyzing operation comprises determining a difference between the current sample of the CA signals and a prior sample of the DRR filtered signals and determining whether the difference exceeds a threshold.

6. The method of claim 5 , further comprising declaring detection of a peak of an R-wave, as the second characteristic, when the difference exceeds the threshold.

7. The method of claim 1 , wherein the analyzing comprises identifying the second characteristic as a peak of an R-wave, the method further comprising determining peak to peak intervals as RR intervals, and the detecting comprises detecting the arrhythmia based on the RR intervals.

8. The method of claim 1 , wherein the analyzing comprises identifying the second characteristic as a noise peak, the method further comprising declaring a noise peak to peak (NPP) interval when a peak to peak interval is below a threshold.

9. The method of claim 8 , further comprising declaring a segment of the CA signals to include excessive noise when a select number of the peak to peak intervals are declared to be NPP intervals.

10. The method of claim 9 , further comprising removing the segment of the CA signals to form noise corrected CA signals, and repeating the applying, comparing, defining, analyzing, and detecting operations utilizing a DRR filter and time constant set for R-wave detection.

11. A system for detecting arrhythmias in cardiac activity, comprising:
memory to store specific executable instructions;
one or more processors configured to execute the specific executable instructions to:
obtain far field cardiac activity (CA) signals for beats;
apply a direction related responsiveness (DRR) filter to the CA signals to produce DRR filtered signals;
compare a current sample from the CA signals to a prior sample from the DRR filtered signals to identify a first characteristic of the CA signals;
define the DRR filter based on the first characteristic identified;
analyze the CA signals in connection with the DRR filtered signals to identify a second characteristic of the CA signals; and
detect at least one of noise or an arrhythmia based on the second characteristic; and
record results of the detecting.

12. The system of claim 11 , wherein the one or more processors are further configured to set a parameter of the DRR filter to a first value when the direction characteristic indicates an increasing trend in the CA signals and set the parameter of the DRR filter a second value when the direction characteristic indicates a decreasing trend in the CA signals.

13. The system of claim 12 , wherein the first value represents a time constant that is shorter than the second value.

14. The system of claim 11 , wherein the one or more processors are further configured to determine a difference between the current sample of the CA signals and a prior sample of the DRR filtered signals and determine whether the difference exceeds a threshold.

15. The system of claim 11 , wherein the one or more processors are further configured to declare detection of a peak of an R-wave, as the second characteristic, when the difference exceeds the threshold.

16. The system of claim 11 , wherein the one or more processors are further configured to identify the second characteristic as a peak of an R-wave, to determine peak to peak intervals as RR intervals, and to detect the arrhythmia based on the RR intervals.

17. The system of claim 11 , wherein the analyzing comprises identifying the peak characteristic as a noise peak, the determining comprises declaring a noise peak to peak (NPP) interval when the peak to peak interval is below a threshold.

18. The system of claim 11 , further comprising an implantable medical device housing the processor and memory.

19. The system of claim 11 , wherein the processor and memory are housed within at least one of a local external device and a remote server.

20. The system claim 11 , wherein the one or more processors are configured to repeat the apply, compare, define, analyze and detect operations in connection with at least one of i) an arrhythmia first pass detection process or ii) an arrhythmia second pass confirmation process.

Assignees

• Pacesetter Inc

Inventors

• Bornzin Gene A
• Dawoud Fady
• Gill Jong
• Rosenberg Stuart
• Qu Fujian
• Malhotra Neha

Classifications

• A61B5/29

  for permanent or long-term implantation · CPC title

• A61B5/352 Primary

  Detecting R peaks, e.g. for synchronising diagnostic apparatus; Estimating R-R interval · CPC title

• A61B5/364

  Detecting abnormal ECG interval, e.g. extrasystoles, ectopic heartbeats · CPC title

• A61B5/283

  Invasive · CPC title

• A61B5/361

  Detecting fibrillation · CPC title