System and method for reconstructing cardiac activation information

• US 9,913,615 B2
• Filed: 11/04/2016
• Issued: 03/13/2018
• Est. Priority Date: 05/02/2011
• Status: Active Grant

• Current Assignee: Topera, Inc (Abbott Laboratories Incorporated), US Department of Veterans Affairs (Government of the United States of America), Regents of the University of California (University of California)
• Original Assignee: Topera, Inc (Abbott Laboratories Incorporated), US Department of Veterans Affairs (Government of the United States of America), Regents of the University of California (University of California)
• Inventors: Narayan, Sanjiv M., Briggs, Carey Robert, Sehra, Ruchir
• Primary Examiner(s): Koharski, Christopher D
• Assistant Examiner(s): Dinga, Roland
• Application Number:
  US15/344,230
• Publication Number:
  US 20170049402A1
• Time in Patent Office: 494 Days
• Field of Search: 600508-519, 607 4- 5, 607 9, 607 25, 607 26
• CPC Class Codes: A61B 2562/046 in a matrix array
• CPC Class Codes: A61B 5/0036 including treatment, e.g., using an implantable medical device, ablating, ventilating
• CPC Class Codes: A61B 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• CPC Class Codes: A61B 5/024 Detecting, measuring or recording pulse rate or heart rate A61B5/0205, A61B5/021 take precedence
• CPC Class Codes: A61B 5/02405 Determining heart rate variability
• CPC Class Codes: A61B 5/0245 by using sensing means generating electric signals, i.e. ECG signals
• CPC Class Codes: A61B 5/0255 Recording instruments specially adapted therefor
• CPC Class Codes: A61B 5/287 Holders for multiple electrodes, e.g. electrode catheters for electrophysiological study [EPS]
• CPC Class Codes: A61B 5/316 Modalities, i.e. specific diagnostic methods
• CPC Class Codes: A61B 5/318 Heart-related electrical modalities, e.g. electrocardiography [ECG]
• CPC Class Codes: A61B 5/341 Vectorcardiography [VCG]
• CPC Class Codes: A61B 5/349 Detecting specific parameters of the electrocardiograph cycle
• CPC Class Codes: A61B 5/361 Detecting fibrillation
• CPC Class Codes: A61B 5/363 Detecting tachycardia or bradycardia
• CPC Class Codes: A61B 5/364 Detecting abnormal ECG interval, e.g. extrasystoles, ectopic heartbeats
• CPC Class Codes: A61B 5/366 Detecting abnormal QRS complex, e.g. widening
• CPC Class Codes: A61B 5/6852 Catheters
• CPC Class Codes: A61B 5/7203 for noise prevention, reduction or removal
• CPC Class Codes: A61B 5/7207 of noise induced by motion artifacts
• CPC Class Codes: A61B 5/7217 of noise originating from a therapeutic or surgical apparatus, e.g. from a pacemaker
• CPC Class Codes: A61B 5/7239 : using differentiation including higher order derivatives
• CPC Class Codes: A61B 5/7246 : using correlation, e.g. template matching or determination of similarity
• CPC Class Codes: A61B 5/7278 : Artificial waveform generation or derivation, e.g. synthesising signals from measured signals A61B5/327 takes precedence
• CPC Class Codes: A61B 5/7282 : Event detection, e.g. detecting unique waveforms indicative of a medical condition A61B5/4094, A61B5/4818, A61B5/349, A61B5/0823 take precedence
• CPC Class Codes: A61B 5/742 : using visual displays A61B5/339 takes precedence

Abstract

In a system and method for reconstructing cardiac activation information, an analysis cardiac signal and a reference cardiac signal are accessed and processed to determine a first point of change in the analysis cardiac signal at which a derivative of the analysis cardiac signal diverges with respect to a derivative of the reference cardiac signal. The signals are processed to determine a second point of change in the analysis cardiac signal at which a different derivative of the analysis cardiac signal with respect to a different derivative of the reference cardiac signal. An activation onset time is assigned in the analysis cardiac signal at a point based on a mathematical association among the first point of change and the second point of change to define cardiac activation indicating a beat in the analysis cardiac signal.

Claims

1. A method of reconstructing cardiac activation information, the method comprising:

accessing, by a computing device, an analysis cardiac signal and a reference cardiac signal obtained from a patient;

processing, by the computing device, the analysis cardiac signal and the reference cardiac signal to determine a first point of change in the analysis cardiac signal at which a derivative of the analysis cardiac signal diverges with respect to a derivative of the reference cardiac signal, the derivative of the analysis cardiac signal and the derivative of the reference cardiac signal being one of zero, first, and second order derivative;

processing, by the computing device, the analysis cardiac signal and the reference cardiac signal to determine a second point of change in the analysis cardiac signal at which a different derivative of the analysis cardiac signal diverges with respect to a different derivative of the reference cardiac signal, the different derivative of the analysis cardiac signal and the different derivative of the reference cardiac signal being a different one of zero, first, and second order derivative; and

assigning an activation onset time in the analysis cardiac signal at a point based on a mathematical association of one or a combination of the first point of change and the second point of change to define a cardiac activation indicating a beat in the analysis cardiac signal.

2. The method of claim 1, wherein the mathematical association is an average of the first point of change and the second point of change representing a plurality of reference cardiac signals processed in relation to the analysis cardiac signal.

3. The method of claim 2, wherein the first point of change and the second point of change are within a predetermined time interval of each other.

4. The method of claim 3, wherein the predetermined time interval is ±

5 ms.

5. The method of claim 2, wherein the plurality is a majority of reference cardiac signals processed in relation to the analysis cardiac signal.

6. The method of claim 1, wherein the mathematical association is a selection comprising:

computing a first difference value of the first point of change minus a first threshold that is associated with the first point of change;

computing a second difference value of the second point of change minus a second threshold that is associated with the second point of change; and

selecting one of the first point of change and the second point of change based on a highest difference value among the first difference value and the second difference value.

7. The method of claim 6, wherein the selection is based on a highest order derivative that is above an associated threshold.

8. The method of claim 1, wherein the first point of change and the second point of change are determined at about the same time point for the analysis cardiac signal and the reference cardiac signal.

9. The method of claim 1, wherein the first point of change and the second point of change are determined from one or more of slope, amplitude, timing, and shape for the analysis cardiac signal and the reference cardiac signal.

10. The method of claim 1, wherein determination of the first point of change comprises:

forming a composite cardiac signal from the analysis cardiac signal and the reference cardiac signal;

determining ratio values at a plurality of points in the analysis cardiac signal, each ratio value representing a difference between the derivative of the reference cardiac signal and a derivative of the composite cardiac signal to a difference between the derivative of the analysis cardiac signal and the derivative of the composite cardiac signal, the derivative of the composite signal being one of zero, first, and second order derivative;

selecting as the first point of change in the analysis cardiac signal a point having a largest ratio value from the determined ratio values.

11. The method of claim 1, wherein determination of the second point of change comprises:

forming a composite cardiac signal from the analysis cardiac signal and the reference cardiac signal;

determining ratio values at a plurality of points in the analysis cardiac signal, each ratio value representing a difference between the different derivative of the reference cardiac signal and a derivative of the composite cardiac signal to a difference between the different derivative of the analysis cardiac signal and a different derivative of the composite cardiac signal, the different derivative of the composite cardiac signal being the different one of zero, first, and second order derivative; and

selecting as the second point of change in the analysis cardiac signal a point having a largest ratio value from the determined ratio values.

12. The method of claim 1, further comprising performing processing and assigning to define multiple cardiac activations indicating beats in the analysis cardiac signal.

13. The method of claim 1, further comprising iteratively selecting the analysis cardiac signal and the reference cardiac signal from a plurality of cardiac signals.

14. The method of claim 1, further comprising:

iteratively selecting pairs of cardiac signals from a plurality of cardiac signals, each pair having an analysis cardiac signal and different reference cardiac signal;

performing processing and assigning for each of the pairs to define multiple cardiac activations indicating beats for the analysis cardiac signal in each of the pairs; and

reconstructing a cardiac activation pattern based on assigned activation onset times of cardiac activations from the plurality of cardiac signals to indicate a source of a cardiac rhythm disorder.

15. A system to reconstruct cardiac activation information comprising:

at least one computing device configured to;

process an analysis cardiac signal and a reference cardiac signal to determine a first point of change in the analysis cardiac signal at which a derivative of the analysis cardiac signal diverges with respect to a derivative of the reference cardiac signal, the derivative of the analysis cardiac signal and the derivative of the reference cardiac signal being one of zero, first, and second order derivative;

process the analysis cardiac signal and the reference cardiac signal to determine a second point of change in the analysis cardiac signal at which a different derivative of the analysis cardiac signal diverges with respect to a different derivative of the reference cardiac signal, the different derivative of the analysis cardiac signal and the different derivative of the reference cardiac signal being a different one of zero, first, and second order derivative; and

assign an activation onset time in the analysis cardiac signal at a point based on a mathematical association of one or a combination of the first point of change and the second point of change to define cardiac activation indicating a beat in the analysis cardiac signal.

16. The system of claim 15, wherein the mathematical association is an average of the first point of change and the second point of change representing a plurality of reference cardiac signals processed in relation to the analysis cardiac signal.

17. The system of claim 16, wherein the first point of change and the second point of change are within a predetermined time interval of each other.

18. The system of claim 17, wherein the predetermined time interval is ±

5 ms.

19. The system of claim 18, wherein the at least one computing device is further configured to:

compute a first difference value of the first point of change minus a first threshold that is associated with the first point of change;

compute a second difference value of the second point of change minus a second threshold that is associated with the second point of change; and

select one of the first point of change and the second point of change based on a highest difference value among the first difference value and the second difference value.

20. The system of claim 19, wherein the selection is based on a highest order derivative that is above an associated threshold.

21. The system of claim 15, wherein the first point of change and the second point of change are determined at about the same time point for the analysis cardiac signal and the reference cardiac signal.

22. The system of claim 15, wherein the first point of change and the second point of change are determined from one or more of slope, amplitude, timing, and shape for the analysis cardiac signal and the reference cardiac signal.

23. The system of claim 15, wherein the at least one computing device is further configured to:

form a composite cardiac signal from the analysis cardiac signal and the reference cardiac signal;

determine ratio values at a plurality of points in the analysis cardiac signal, each ratio value representing a difference between the derivative of the reference cardiac signal and a derivative of the composite cardiac signal to a difference between the derivative of the analysis cardiac signal and the derivative of the composite cardiac signal, the derivative of the composite signal being one of zero, first, and second order derivative; and

select as the first point of change in the analysis cardiac signal a point having a largest ratio value from the determined ratio values.

24. The system of claim 15 wherein at least one computing device is further configured to:

form a composite cardiac signal from the analysis cardiac signal and the reference cardiac signal;

determine ratio values at a plurality of points in the analysis cardiac signal, each ratio value representing a difference between the different derivative of the reference cardiac signal and a different derivative of the composite cardiac signal to a difference between the different derivative of the analysis cardiac signal and the different derivative of the composite cardiac signal, the different derivative of the composite cardiac signal being the different one of zero, first, and second order derivative; and

select as the second point of change in the analysis cardiac signal a point having a largest ratio value from the determined ratio values.

25. The system of claim 15, wherein the at least one computing device is further configured to perform to perform processing and assigning to define multiple cardiac activations indicating beats in the analysis cardiac signal.

26. The system of claim 15, wherein the at least one computing device is further configured to iteratively select the analysis cardiac signal and the reference cardiac signal from a plurality of cardiac signals.

27. The system of claim 15, wherein at least one computing device is further configured to:

iteratively select pairs of cardiac signals from a plurality of cardiac signals, each pair having an analysis cardiac signal and different reference cardiac signal;

perform processing and assigning for each of the pairs to define multiple cardiac activations indicating beats for the analysis cardiac signal in each of the pairs; and

reconstruct a cardiac activation pattern based on assigned activation onset times of cardiac activations from the plurality of cardiac signals to indicate a source of a cardiac rhythm disorder.