Region of interest focal source detection using comparisons of R-S wave magnitudes and LATs of RS complexes

Patent metadata

Field	Value
Publication number	US-11006887-B2
Application number	US-201715404228-A
Country	US
Kind code	B2
Filing date	Jan 12, 2017
Priority date	Jan 14, 2016
Publication date	May 18, 2021
Grant date	May 18, 2021

Abstract

A system and method of identifying focal sources is presented. The method can comprise detecting, via sensors, electro-cardiogram (ECG) signals over time, each ECG signal detected via one of the sensors having a location in a heart and indicating electrical activity of the heart, each signal comprising at least an R wave and an S wave; creating an R-S map comprising an R-to-S ratio for each of the ECG signals, the R-to-S ratio comprising a ratio of absolute magnitude of the R wave to absolute magnitude of the S wave; identifying, for each of the ECG signals, local activation times (LATs); and correlating the R-to-S ratios for the ECG signals on the R-S map and the identified LATs and using the correlation to identify the focal sources.

First claim

What is claimed is:

1. A method comprising:
acquiring, via a plurality of sensors, electro-cardiogram (ECG) signals over time, each ECG signal acquired via one of the plurality of sensors and representing electrical activity of one of a plurality of different areas of a heart, each ECG signal comprising at least an R wave and an S wave;
determining local activation times (LATs) of each ECG signal, each LAT of a respective ECG signal corresponding to acquired electrical activity at a different point in time;
chronologically ordering groups of the ECG signals, each group determined to be part of a same cardiac activation cycle, based on LATs of each group of ECG signals;
generating first mapping information for visually indicating, at locations on a local activation time (LAT) map, a number of instances, during a period of time that includes multiple cardiac activation cycles, in which the LATs of each ECG signal are earlier than the LATs of other ECG signals belonging to the same chronologically ordered group; and
generating second mapping information for visually indicating, at locations on an R-S map corresponding to the same locations on the LAT map, sizes of R-to-S ratios for each ECG signal in the period of time that includes multiple cardiac activation cycles, each R-to-S ratio comprising a ratio of a magnitude of the R wave to a magnitude of the S wave,
wherein, potential focal sources of activation of the heart are identified based on the visually indicated number of times at each location on the LAT map and the visually indicated sizes of the R-to-S ratios at each corresponding location on the R-S map.

2. The method of claim 1 , wherein determining the LATs further comprises:
calculating a derivative for each of the R-S ratios; and
identifying an earliest activation LAT having a largest negative value of the calculated derivative of the R-S ratio.

3. The method of claim 2 , wherein generating second mapping information further comprises:
determining, from the plurality of ECG signals, a strongest ECG signal having a largest difference between the magnitude of the R wave and the magnitude of the S wave, and determining a location of the sensor having the strongest ECG signal, wherein at least one of the focal sources is identified as the location of the sensor having the strongest ECG signal and the earliest activation LAT.

4. The method of claim 3 ,
wherein the number of times at each location on the LAT map and the sizes of the R-to-S ratios on the R-S map are visually indicated by one of color, texture and size.

5. The method of claim 1 , further comprising determining a dominant focal source from the identified focal sources.

6. The method of claim 5 , determining the dominant focal source further comprises:
comparing cycle lengths of each of the identified focal sources with temporally-corresponding cycle lengths of a previously acquired signal; and
determining the dominant focal source as the identified focal source having the cycle length corresponding most closely to the temporally-corresponding cycle length of the previously acquired signal.

7. The method of claim 1 , wherein
the LAT map comprises a first array of a number of columns and a number of rows, the first array visually indicating, for each electrode, the number of early activation times at a location on the first array, and
the R-S map comprises a second array of a same number of columns and a same number rows as the first array, the second array visually indicating, for each electrode, the sizes of R-to-S ratios at the corresponding locations.

8. A system comprising:
a plurality of sensors each configured to acquire one of a plurality of electro-cardiogram (ECG) signals over time representing electrical activity of one of a plurality of different areas of a heart, each ECG signal comprising an R wave and an S wave; and
a processing device comprising one or more processors configured to:
determine local activation times (LATs) of each ECG signal, each LAT of a respective ECG signal corresponding to acquired electrical activity at a different point in time;
chronologically order groups of the ECG signals, each group determined to be part of a same activation cycle, based on LATs of each group of ECG signals;
generate first mapping information for visually indicating, at locations on a local activation time (LAT) map, a number of instances, over a period of time that includes multiple cardiac activation cycles, in which the LATs of each ECG signal, are earlier than the LATs of other ECG signals belonging to the same chronologically ordered group; and
generate second mapping information for visually indicating, at locations on an R-S map corresponding to the same locations on the LAT map, sizes of R-to-S ratios for each ECG signal in the period of time that includes multiple cardiac activation cycles, each R-to-S ratio comprising a ratio of a magnitude of the R wave to a magnitude of the S wave,
wherein potential focal sources of activation of the heart are identified based on the visually indicated number of times at each location on the LAT map and the visually indicated sizes of the R-to-S ratios at each corresponding location on the R-S map.

9. The system of claim 8 , wherein the processing device is further configured to:
calculate a derivative for each of the R-S ratios; and
identify an earliest activation LAT having a largest negative value of the calculated derivative of the R-S ratio.

10. The system of claim 9 , wherein the processing device is further configured to:
determine, from the plurality of ECG signals, a strongest ECG signal having a largest difference between the magnitude of the R wave and the magnitude of the S wave, and determining a location of the sensor having the strongest ECG signal, wherein at least one of the focal sources is identified as the location of the sensor having the strongest ECG signal and the earliest activation LAT.

11. The system of claim 10 ,
wherein
the number of times at each location on the LAT map and the sizes of the R-to-S ratios on the R-S map are visually indicated by one of color, texture and size.

12. The system of claim 8 , wherein the processing device is further configured to determine a dominant focal source from the identified focal sources.

13. The system of claim 12 , wherein the processing device is further configured to:
compare cycle lengths of each of the identified focal sources with temporally-corresponding cycle lengths of a previously acquired signal; and
determine the dominant focal source as the identified focal source having the cycle length corresponding most closely to the temporally-corresponding cycle length of the previously acquired signal.

14. A non-transitory computer readable storage medium in which computer program instructions are stored, which instructions, when executed by a computer, cause the computer to perform the steps of:
acquiring, via a plurality of sensors, electro-cardiogram (ECG) signals over time, each ECG signal acquired via one of the plurality of sensors and representing electrical activity of one of a plurality of different areas of a heart, each ECG signal comprising at least an R wave and an S wave;
determining local activation times (LATs) of each ECG signal, each LAT of a respective ECG signal corresponding to acquired electrical activity at a different point in time;
chronologically ordering groups of the ECG signals, each group determined to be part of a same activation cycle, based on LATs of each group of ECG signals;
generating first mapping information for visually indicating, at locations on a local activation

Assignees

• Biosense Webster Israel Ltd

Inventors

• Urman Roy
• Bar-Tal Meir
• Ben Zrihem Yaniv
• Zeidan Ziyad
• Hayam Gal
• Goldberg Stanislav
• Verma Atul
• Amos Yariv Avraham
• Houben Richard P M

Classifications

• A61B18/1492

  having a flexible, catheter-like structure, e.g. for heart ablation (A61B18/1477 takes precedence) · CPC title

• A61B5/366

  Detecting abnormal QRS complex, e.g. widening · CPC title

• A61B5/287

  Holders for multiple electrodes, e.g. electrode catheters for electrophysiological study [EPS] · CPC title

• A61B5/367

  Electrophysiological study [EPS], e.g. electrical activation mapping or electro-anatomical mapping · CPC title

• A61B5/346

  Analysis of electrocardiograms · CPC title