Detection and localization of cardiac fast firing

Patent metadata

Field	Value
Publication number	US-11229392-B2
Application number	US-201916353534-A
Country	US
Kind code	B2
Filing date	Mar 14, 2019
Priority date	Mar 15, 2018
Publication date	Jan 25, 2022
Grant date	Jan 25, 2022

Abstract

Systems and methods for cardiac fast firing (e.g., atrial fast firing) detection perform frequency analysis on channels of collected cardiac waveform data and test the data for outlier frequency complex content that is of higher frequency than baseline frequency complex content associated with cardiac fibrillation (e.g., atrial fibrillation) or other arrhythmogenic activity. Anatomical regions from whence the cardiac fast firing originates can be displayed in real time on an epicardial surface map via a graphical display, aiding administration of therapy. Prior to such detection, QRST complex removal can be performed to ensure that ventricular activity does not infect the atrial fast firing analysis. A frequency-based method for QRST complex removal is also disclosed.

First claim

The invention claimed is:

1. A processor-implemented method to detect cardiac fast firing activity of a heart, the method comprising:
collecting cardiac waveform data from a measurement system configured to acquire body surface electrical measurements corresponding to a plurality of channels from body surface electrodes adapted to be placed on a patient's body surface;
using a processor to perform frequency analysis of the collected cardiac waveform data for each of the plurality of channels over a moving window;
using the processor to identify a proper subset of the channels exhibiting a fast-firing frequency peak within an outlier frequency cluster having a dominant frequency that is higher than a dominant frequency of a baseline frequency cluster corresponding to fibrillatory cardiac activity during a given time window within which the frequency analysis was performed; and
using the processor to map the proper subset of channels identified as fast-firing in the given time window to one or more spatial regions of the heart.

2. The method of claim 1 , wherein the frequency analysis further comprises removing QRST content from each channel of the collected cardiac waveform data.

3. The method of claim 2 , wherein removing QRST content further comprises:
performing a frequency analysis on an electrocardiographic signal derived from one of the plurality of channels to generate signal frequency plot data;
performing a frequency analysis on an identified QRST frequency template to generate template frequency plot data;
subtracting the template frequency plot data from the signal frequency plot data to generate frequency plot data of a QRST-removed electrocardiographic signal corresponding to the electrocardiographic signal; and
repeating the signal frequency plot data generation and the subtraction for additional channels in the plurality of channels.

4. The method of claim 3 , wherein an amount of power removed from the electrocardiographic signal in the QRST-removed electrocardiographic signal is based on a provided number of QRS complexes in the electrocardiographic signal, and wherein the template frequency plot data is not normalized.

5. The method of claim 1 , further comprising generating a graphical output indicative of at least one of the time and/or anatomical location of fast-firing activity.

6. The method of claim 1 , further comprising controlling delivery of a therapy based on an anatomical location of fast-firing activity that corresponds to one of the one or more spatial regions of the heart.

7. The method of claim 1 , wherein the proper subset of the channels exhibiting a fast-firing frequency peak is identified based on determining respective channels from among the plurality of channels that have a mean dominant frequency that is at least one standard deviation greater than a mean dominant frequency of the baseline frequency cluster during cardiac fibrillation.

8. The method of claim 1 , wherein the proper subset of the channels exhibiting a fast-firing frequency peak is identified based on:
providing a frequency value as a frequency threshold either manually as a user input or via an automatic threshold value generator, the frequency threshold being between the dominant frequency of the outlier frequency cluster and the dominant frequency of the baseline frequency cluster;
comparing dominant frequencies of individual channels from the among plurality of channels against the frequency threshold during the given time window; and
determining channels from among the plurality of channels exhibiting a dominant frequency greater than the frequency threshold to be fast-firing channels within the proper subset of the channels.

9. The method of claim 8 , wherein the frequency threshold is a value in the range of about 8 Hz to about 10 Hz.

10. The method of claim 8 , further comprising:
providing an integer value as a channel number threshold indicative of a minimum number of channels, either manually as a user input or via an automatic determination;
determining that the fast-firing event has occurred based on a number of channels determined to be fast-firing channels exceeding the channel number threshold during the given time window.

11. The method of claim 8 , further comprising anatomically localizing the fast-firing activity based on the determined fast-firing channels.

12. The method of claim 1 , wherein the proper subset of the channels exhibiting a fast-firing frequency peak is identified based on:
analyzing frequency plot data of each of a plurality of given channels from among the plurality of channels to test for changes in a dominant frequency over multiple windowed time frames; and
identifying one or more of the plurality of given channels as a fast-firing channel within the proper subset of the channels during one or more time frames that the dominant frequency of the identified channel is in a higher-frequency range, based on the identified channel showing substantial movement in dominant frequency from a lower-frequency range to the higher-frequency range, or from the higher-frequency range to the lower-frequency range.

13. The method of claim 12 , wherein the lower-frequency range is about 3 Hz to about 8 Hz, and wherein the higher-frequency range is about 8 Hz to about 12 Hz.

14. The method of claim 1 , wherein the proper subset of the channels exhibiting a fast-firing frequency peak is identified based on comparing frequency plot data of a given channel from among the plurality of channels to frequency plot data of one or more spatially neighboring channels from among the plurality of channels during the given time window.

15. A system comprising:
a measurement system configured to acquire cardiac waveform data based on body surface electrical measurements corresponding to a plurality of channels from body surface electrodes adapted to be placed on a patient's body surface;
a processor configured to:
perform frequency analysis of the acquired cardiac waveform data for each of the plurality of channels over a moving window;
identify a proper subset of the channels exhibiting a fast-firing frequency peak within an outlier frequency cluster having a dominant frequency that is higher that a dominant frequency of a baseline frequency cluster corresponding to fibrillatory cardiac activity during a given time window within which the frequency analysis was performed; and
map the proper subset of the channels identified as fast-firing in the given time window to one or more spatial regions of a heart.

16. The system of claim 15 , wherein the frequency analysis further comprises removing QRST content from each channel of the collected cardiac waveform data.

17. The system of claim 15 , wherein the processor is further configured to generate a graphical output indicative of at least one of the time and/or anatomical location of fast-firing activity.

18. The system of claim 15 , further comprising a therapy system configured to control delivery of a therapy based on an anatomical location of fast-firing activity that corresponds to one of the one or more spatial regions of the heart.

19. The system of claim 15 , wherein the proper subset of the channels exhibiting a fast-firing frequency peak is identified based on determining respective channels from among the plurality of channels that have a mean dominant frequency that is at least one standard deviation greater than a mean dominant frequency of the baseline frequency cluster during cardiac fibrillation.

20. The system of claim 15

Assignees

• Cardioinsight Technologies Inc

Inventors

• Jia Ping
• Zeng Qingguo
• Laske Timothy G
• Lou Qing

Classifications

• A61B5/339

  Displays specially adapted therefor · CPC title

• A61B5/349 Primary

  Detecting specific parameters of the electrocardiograph cycle · CPC title

• A61B5/363

  Detecting tachycardia or bradycardia · CPC title

• A61B5/361

  Detecting fibrillation · CPC title

• A61B5/7257

  using Fourier transforms · CPC title