Method and system to detect p-waves in cardiac arrhythmic patterns

Patent metadata

Field	Value
Publication number	US-2021076969-A1
Application number	US-202017086507-A
Country	US
Kind code	A1
Filing date	Nov 2, 2020
Priority date	May 7, 2018
Publication date	Mar 18, 2021
Grant date	—

Abstract

Methods and systems are provided for detecting arrhythmias in cardiac activity. The methods and systems declare a current beat, from the CA signals, to be a candidate beat or an ineligible beat based on whether the current beat satisfies the rate based selection criteria. The determining and declaring operations are repeated for multiple beats to form an ensemble of candidate beats. The method and system calculate a P-wave segment ensemble from the ensemble of candidate beats, perform a morphology-based comparison between the P-wave segment ensemble and at least one of a monophasic or biphasic template, declare a valid P-wave to be present within the CA signals based on the morphology-based comparison, and utilize the valid P-wave in an arrhythmia detection process to determine at least one of an arrhythmia entry, arrhythmia presence or arrhythmia exit.

First claim

What is claimed is:

1 . A computer implemented method for detecting arrhythmias in far field cardiac activity (CA) signals collected by two or more electrodes located remote from a right atrium, comprising:
under control of one or more processors configured with specific executable instructions, declaring candidate beats, from the CA signals for a series of beats, based on whether current beats within the series of beats satisfy a rate based selection criteria; calculating a P-wave segment ensemble by combining candidate P-wave segments from the far field CA signals for an ensemble of the candidate beats; performing a morphology-based comparison between the P-wave segment ensemble and at least one of a template; declaring a valid P-wave to be present within the CA signals based on the morphology-based comparison; and utilizing the valid P-wave in an arrhythmia detection process to determine at least one of an arrhythmia entry, arrhythmia presence or arrhythmia exit.

2 . The method of claim 1 , wherein the rate based selection criteria represents a RR interval rate criteria in which a beat is disregard, as an ineligible beat, when the RR interval is outside of a predetermined range.

3 . The method of claim 1 , further comprising determining the candidate beats by applying a two-part selection test that includes i) determining whether an RR interval of a candidate beat is within a predetermined range and ii) determining whether the candidate beat is greater or shorter than a previous beat, and if shorter, determining whether the candidate beat has a duration that is within a range of the previous beat.

4 . The method of claim 1 , further comprising:
overlaying a P-wave search window onto a candidate segment within the corresponding candidate beats to obtain candidate P-wave segments; combining the candidate P-wave segments to form a P-wave combination; and determining whether a signal characteristic of interest from the P-wave combination exceeds one or more P-wave limits.

5 . The method of claim 4 , further comprising truncating the candidate P-wave segments when a signal characteristic exceeds one or more P-wave limits, the calculating operation calculating a final P-wave segment ensemble based on the candidate P-wave segments after truncation.

6 . The method of claim 1 , further comprising de-trending the ensemble of candidate beats to remove baseline drift from individual P-wave segments for corresponding candidate beats.

7 . The method of claim 1 , further comprising normalizing the P-wave segment ensemble before performing the correlating operation.

8 . The method of claim 1 , further comprising correlating a first P-wave segment, for a first beat from the ensemble of candidate beats, with the P-wave segment ensemble for the ensemble of candidate beats for morphology similarity analysis.

9 . The method of claim 1 , wherein the declaring operation further comprises declaring the valid P-wave to be present within the CA signals when the correlation between the P-wave segment ensemble and at least one of a monophasic template or a biphasic template satisfies a correlation threshold.

10 . The method of claim 1 , wherein the declaring operation further comprises declaring the P-wave segment ensemble to not include a P-wave when the correlation between the P-wave segment ensemble and both of the monophasic and biphasic templates do not satisfy a correlation threshold.

11 . A system for detecting arrhythmias in far field cardiac activity (CA) signals collected by two or more electrodes located remote from a right atrium, comprising:
memory to store specific executable instructions; one or more processors configured to execute the specific executable instructions for:
declaring candidate beats, from the CA signals for a series of beats, based on whether current beats within the series of beats satisfy a rate based selection criteria;
calculating a P-wave segment ensemble by combining candidate P-wave segments from the far field CA signals for an ensemble of the candidate beats;
performing a morphology-based comparison between the P-wave segment ensemble and at least one of a template;
declaring a valid P-wave to be present within the CA signals based on the morphology-based comparison; and
utilizing the valid P-wave in an arrhythmia detection process to determine at least one of an arrhythmia entry, arrhythmia presence or arrhythmia exit.

12 . The system of claim 11 , wherein the rate based selection criteria represents a RR interval rate criteria in which a beat is disregard, as the ineligible beat, when the RR interval is outside of a predetermined range.

13 . The system of claim 11 , wherein the one or more processors are configured to determine the candidate beats by applying a two-part selection test that includes i) determining whether an RR interval of a candidate beat is within a predetermined range and ii) determining whether the candidate beat is greater or shorter than a previous beat, and if shorter, determining whether the candidate beat has a duration that is within a range of the previous beat.

14 . The system of claim 11 , wherein the one or more processors are configured to further:
overlay a P-wave search window onto a candidate segment within corresponding candidate beats to obtain candidate P-wave segments; combine the candidate P-wave segments to form a P-wave combination; and determine whether a signal characteristic of interest from the P-wave combination exceeds one or more P-wave limits.

15 . The system of claim 14 , wherein the one or more processors are further configured to truncate the candidate P-wave segments when a signal characteristic exceeds one or more P-wave limits, the calculating operation calculating a final P-wave segment ensemble based on the candidate P-wave segments after truncation.

16 . The system of claim 11 , wherein the one or more processors are further configured to de-trend the ensemble of candidate beats to remove baseline drift from individual P-wave segments for corresponding candidate beats.

17 . The system of claim 11 , wherein the one or more processors are further configured to normalize the P-wave segment ensemble before performing the correlating operation.

18 . The system of claim 11 , wherein the one or more processors are further configured to correlate a first P-wave segment, for a first beat from the ensemble of candidate beats, with the P-wave segment ensemble for the ensemble of candidate beats for morphology similarity analysis.

19 . The system of claim 11 , wherein the one or more processors are further configured to declare the valid P-wave to be present within the CA signals when the correlation between the P-wave segment ensemble and at least one of a monophasic template or a biphasic template satisfies a correlation threshold.

20 . The system of claim 11 , wherein the one or more processors are further configured to declare the P-wave segment ensemble to not include a P-wave when the correlation between the P-wave segment ensemble and both of the monophasic and biphasic templates do not satisfy a correlation threshold.

Assignees

• Pacesetter Inc

Inventors

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

Classifications

• A61B5/02405

  Determining heart rate variability · CPC title

• A61B5/352

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

• A61N1/3956

  Implantable devices for applying electric shocks to the heart, e.g. for cardioversion · CPC title

• A61B5/35 Primary

  by template matching · CPC title

• A61B5/0245

  by using sensing means generating electric signals, {i.e. ECG signals} · CPC title