Method and system for second pass confirmation of detected cardiac arrhythmic patterns

Patent metadata

Field	Value
Publication number	US-11426112-B2
Application number	US-202016855466-A
Country	US
Kind code	B2
Filing date	Apr 22, 2020
Priority date	May 7, 2018
Publication date	Aug 30, 2022
Grant date	Aug 30, 2022

Abstract

A computer implemented method and system for confirming a device documented arrhythmia in cardiac activity are provided. The method is under control of one or more processors configured with executable instructions. The method obtains a cardiac activity (CA) data set that includes CA signals for a series of cardiac events and includes device documented (DD) markers within the series of cardiac events. The device documented markers are indicative of atrial fibrillation (AF) detected by the ICM utilizing an on-board R-R interval irregularity (ORI) process to analyze the CA signals. The method applies a feature enhancement function to the CA signals to form modified CA signals with enhanced sinus features and analyzes the enhanced sinus features in the modified CA signals. The method utilized a confirmatory feature detection process to identify false AF detection by the ORI process. The method records a result of the analysis identifying false AF detection by the ORI process.

First claim

What is claimed is:

1. A computer implemented method for confirming an arrhythmia, comprising:
under control of one or more processors configured with executable instructions,
a) sensing cardiac activity (CA) signals utilizing a combination of electrodes;
b) implementing a first detection process that includes:
b1) comparing an amplitude of the CA signals to a first sensitivity level to detect a series of first sensitivity based R-waves in the CA signals;
b2) determining intervals between consecutive R-R waves for the series of first sensitivity based R waves in the CA signals; and
b3) detecting an arrhythmia episode based on the intervals between the consecutive R-R waves for the series of first sensitivity based R waves in the CA signals;

c) storing a segment of the CA signals occurring within the arrhythmia episode; and
d) in response to detection of the arrhythmia episode, implementing a confirmatory detection process that includes:
d1) adjusting a parameter of a second sensitivity level based on at least one of P-wave or R-wave amplitudes occurring in the segment of CA signals stored;
d2) comparing the amplitude of the CA signals, in the segment of CA signals stored, to the second sensitivity level to detect a series of second sensitivity based R waves that includes one or more R waves under sensed by the first detection process; and
d3) confirming or rejecting the arrhythmia episode based on consecutive R-R intervals for the series of second sensitivity based R waves that includes the one or more R waves under sensed by the first detection process.

2. The method of claim 1 , wherein operations at a), b), c) and d) are performed iteratively in real time while a patient is experiencing the arrhythmia episode, and the adjusting is performed in real time to form an adaptive second sensitivity level based on at least one of P-wave or R-wave amplitudes.

3. The method of claim 1 , wherein the confirming or rejecting further comprises:
determining intervals between consecutive R-R waves for the series of second sensitivity based R waves in the segment of the CA signals stored; and
determining whether the intervals between consecutive R-R waves for the series of second sensitivity based R waves indicate a brady episode.

4. The method of claim 1 , furthering comprising detecting one or more P-waves in the segment of the CA signals stored and rejecting the detection of the arrhythmia episode when the number of P-waves in the stored CA signals is greater than a threshold.

5. The method of claim 3 , wherein the arrhythmia episode represents an atrial fibrillation (AF) episode, the method further comprising performing P-wave detection to determine whether P-waves are present in the segment of CA signals stored, and confirming or rejecting the AF episode based on a presence of one or more P waves in the segment of the CA signals stored.

6. The method of claim 1 , wherein, when the arrhythmia episode is rejected, the method further comprising classifying the segment of the CA signals to represent a false positive.

7. The method of claim 6 , further comprising tracking a number of the false positives that are initially declared to represent arrhythmia episodes by the first detection process.

8. The method of claim 1 , wherein the first detection process includes providing device documented (DD) markers in connection with each of the first sensitivity based R-waves that are detected, and wherein the confirmatory detection process includes providing confirmatory markers in connection with each of the second sensitivity based R-waves that are detected, the confirming or rejecting based on the DD and confirmatory markers.

9. The method of claim 8 , further comprising determining whether a difference exists between the confirmatory and DD markers, the confirming or rejecting including rejecting the arrhythmia episode when the difference exists between the confirmatory and DD markers.

10. The method of claim 1 , further comprising performing premature ventricular contraction (PVC) detection to determine whether one or more PVC are present in the segment of CA signals stored, confirming or rejecting the arrhythmia episode based on a presence of one or more PVCs in the segment of the CA signals stored.

11. The method of claim 1 , furthering comprising comparing a duration between consecutive R-R waves to an asystole threshold and, when the duration exceeds the asystole threshold, the method detecting an asystole episode.

12. The method of claim 1 , wherein the sensing the CA signals includes sensing the CA signals at an implantable cardiac monitor (ICM) located remote from the heart utilizing implantable electrodes provided on the ICM, the method further comprising determining whether the CA signals exhibit a non-physiologic characteristic indicative of at least one of i) motion artifacts or ii) partial or complete loss of contact at the implantable electrodes on the ICM and rejecting the detection of a pause event in response to the detection of partial or complete loss of contact.

13. The method of claim 1 , further comprising determining when an extent or degree of at least one of false R-wave detection or false AF detection exceeds a threshold and based thereon adjusting the parameter of the second sensitivity level.

14. The method of claim 13 , wherein the determining the extent or degree includes determining when a threshold is exceeded by at least one of a number of under-sensed R-waves, a number of P-waves classified as R-waves, a number of T-waves classified as R-waves, a number of noise artifacts classified as R-waves or a number of post ventricular contractions.

15. A system for confirming an arrhythmias, comprising:
electrodes;
memory to store specific executable instructions;
one or more processors configured to execute the specific executable instructions for:
a) sensing cardiac activity (CA) signals utilizing the electrodes;
b) implementing a first detection process that includes:
b1) comparing an amplitude of the CA signals to a first sensitivity level to detect a series of first sensitivity based R-waves in the CA signals;
b2) determining intervals between consecutive R-R waves for the series of first sensitivity based R waves in the CA signals; and
b3) detecting an arrhythmia episode based on the consecutive R-R intervals for the series of first sensitivity based R waves in the CA signals;

c) storing, in the memory, a segment of the CA signals occurring prior to an event of interest within the arrhythmia episode; and
d) in response to detection of the arrhythmia episode, implementing a confirmatory detection process that includes:
d1) adjusting a parameter of the second sensitivity level based on at least one of P-wave or R-wave amplitudes occurring in the segment of CA signals stored;
d2) comparing the amplitude of the CA signals, in the segment of CA signals stored, to a second sensitivity level to detect a series of second sensitivity based R waves that includes one or more R waves under sensed by the first detection process; and
d3) confirming or rejection the arrhythmia episode based on consecutive R-R intervals for the series of second sensitivity based R waves that includes the one or more R waves under sensed by the first detection process.

16. The system of claim 15 , wherein the one or more processors are configured to iteratively perform the operations at a), b), c) and d) in real time while a patient is experiencing the arrhythmia episode, and the adjusting is performed in real time to form an adaptive second sensitivity level based on at least one of P-wave

Assignees

• Pacesetter Inc

Inventors

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

Classifications

• A61B5/29

  for permanent or long-term implantation · CPC title

• A61B5/361 Primary

  Detecting fibrillation · CPC title

• G06F2218/16

  by matching signal segments · CPC title

• G16H20/40

  relating to mechanical, radiation or invasive therapies, e.g. surgery, laser therapy, dialysis or acupuncture · CPC title

• A61B5/352

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