System and method for reconstructing cardiac activation information

• US 9,055,876 B2
• Filed: 11/07/2013
• Issued: 06/16/2015
• 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), United States Department of Veterans Affairs Office of General Counsel, 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, Briggs, Carey Robert
• Primary Examiner(s): Voorhees, Catherine
• Assistant Examiner(s): Dinga, Roland
• Application Number:
  US14/074,619
• Publication Number:
  US 20140066787A1
• Time in Patent Office: 586 Days
• Field of Search: 600/301, 600/481, 600/483, 600485-519, 607 4- 5, 607/9, 607/25, 607/26
• US Class Current: 1/1
• CPC Class Codes: A61B 18/02 by cooling, e.g. cryogenic techniques devices for cooling specific reflex points of the body within cell-life limits A61H39/06
• CPC Class Codes: A61B 18/12 by passing a current through the tissue to be heated, e.g. high-frequency current
• CPC Class Codes: A61B 18/18 by applying electromagnetic radiation, e.g. microwaves radiation therapy A61N5/00
• CPC Class Codes: A61B 2018/00577 Ablation
• CPC Class Codes: A61B 2562/046 in a matrix array
• CPC Class Codes: A61B 5/0002 Remote monitoring of patients using telemetry, e.g. transmission of vital signals via a communication network A61B5/07 takes precedence; transmission systems for measured values G08C; transmission H04B; transmission of digital information H04L; wireless communication networks H04W
• 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 5/02405 Determining heart rate variability
• 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 5/341 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 5/6852 Catheters
• CPC Class Codes: A61B 5/7203 for noise prevention, reduction or removal
• 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
• CPC Class Codes: A61B 5/743 : Displaying an image simultaneously with additional graphical information, e.g. symbols, charts, function plots

Abstract

An example system and method of processing cardiac activation information are disclosed. The method includes accessing a first cardiac signal and a second cardiac signal obtained from a patient. The first cardiac signal and the second cardiac signal are processed to determine whether there is a point of change in the first cardiac signal at which a derivative of the first cardiac signal diverges with respect to a derivative of the second cardiac signal above a threshold. An activation onset time is assigned in the first cardiac signal at the point of change to define a cardiac activation if the point of change is in the first cardiac signal.

Claims

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

accessing a first cardiac signal and a second cardiac signal obtained from a patient;

processing the first cardiac signal and the second cardiac signal to determine whether there is a point of change in the first cardiac signal at which a derivative of the first cardiac signal diverges with respect to a derivative of the second cardiac signal above a threshold; and

assigning an activation onset time in the first cardiac signal at the point of change to define a cardiac activation if the point of change is in the first cardiac signal.

2. The method of claim 1, wherein the derivative of the first cardiac signal and the derivative of the second cardiac signal are selected from the group consisting of a zero order derivative, a first order derivative, a second order derivative, a higher order derivative, and combinations thereof.

3. The method of claim 1, wherein the derivative of the first cardiac signal and the derivative of the second cardiac signal are zero order derivatives.

4. The method of claim 1, wherein the derivative of the first cardiac signal and the derivative of the second cardiac signal are first order derivatives.

5. The method of claim 1, wherein the derivative of the first cardiac signal and the derivative of the second cardiac signal are second order derivatives.

6. The method of claim 1, further comprising obtaining the first cardiac signal and the second cardiac signal from the patient using a first sensor and a second sensor, respectively.

7. The method of claim 6, wherein the first cardiac signal and the second cardiac signal are obtained contemporaneously from the patient.

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

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

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

forming a composite cardiac signal from the first cardiac signal and the second cardiac signal;

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

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

11. The method of claim 1, wherein the threshold is higher than a noise level associated with the first cardiac signal and the second cardiac signal.

12. The method of claim 11, wherein a point of change at or below the noise level is associated with one or more signals from a heart, respiratory system, gastrointestinal tract, neurological system and electronic interference.

13. The method of claim 1, further comprising:

matching at least one characteristic of the first cardiac signal to at least one characteristic of a reference cardiac signal in a catalog of cardiac signals if the point of change is not in the first cardiac signal; and

assigning an activation onset time in the first cardiac signal as an activation onset time of the reference cardiac signal to define a cardiac activation in the first cardiac signal.

14. The method of claim 1, further comprising performing accessing, processing and assigning to define multiple cardiac activations in the first cardiac signal.

15. The method of claim 1, further comprising iteratively accessing the first cardiac signal and the second cardiac signal from a plurality of cardiac signals.

16. The method of claim 1, further comprising:

iteratively accessing pairs of cardiac signals from a plurality of cardiac signals, each pair having a first cardiac signal and different second cardiac signal;

performing processing and assigning for each of the pairs to define multiple cardiac activations in the first 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.

17. The method of claim 16, further comprising displaying the cardiac activation pattern as reconstructed to facilitate treatment of cardiac tissue at the source to treat the cardiac rhythm disorder.

18. A system to process cardiac activation information, the system comprising:

at least one computing device to;

access a first cardiac signal and a second cardiac signal obtained from a patient;

process the first cardiac signal and the second cardiac signal to determine whether there is a point of change in the first cardiac signal at which a derivative of the first cardiac signal diverges with respect to a derivative of the second cardiac signal above a threshold; and

assign an activation onset time in the first cardiac signal at the point of change to define a cardiac activation if the point of change is in the first cardiac signal.

19. The system of claim 18, wherein the derivative of the first cardiac signal and the derivative of the second cardiac signal are one of a zero order derivative, a first order derivative, a second order derivative, and a higher order derivative, and combinations thereof.

20. The system of claim 18, wherein the derivative of the first cardiac signal and the derivative of the second cardiac signal are zero order derivatives.

21. The system of claim 18, wherein the derivative of the first cardiac signal and the derivative of the second cardiac signal are first order derivatives.

22. The system of claim 18, wherein the derivative of the first cardiac signal and the derivative of the second cardiac signal are second order derivatives.

23. The system of claim 18, further comprising a computer readable medium comprising instructions, which when executed by the at least one computing device, cause the at least one computing device to access, process and assign.

24. The system of claim 18, wherein the point of change is determined at about the same time point for both the first cardiac signal and the second cardiac signal.

25. The system of claim 18, wherein the point of change is determined from one or more of slope, amplitude, timing and shape for the first cardiac signal and the second cardiac signal.

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

form a composite cardiac signal from the first cardiac signal and the second cardiac signal;

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

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

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

match at least one characteristic of the first cardiac signal to at least one characteristic of a reference cardiac signal in a catalog of cardiac signals if the point of change is not in the first cardiac signal; and

assign an activation onset time in the first cardiac signal as an onset time of the reference cardiac signal to define a cardiac activation in the first cardiac signal.

28. The system of claim 18, wherein the at least one computing device is further to access, process and assign to define multiple cardiac activations in the first cardiac signal.

29. The system of claim 18, wherein the at least one computing device is further to iteratively access the first cardiac signal and the second cardiac signal from a plurality of obtained cardiac signals.

30. The system of claim 18, further comprising a catheter with at least a first sensor and a second sensor to obtain from the patient the first cardiac signal and the second cardiac signal, respectively.

31. The system of claim 30, wherein the first cardiac signal and the second cardiac signal are obtained contemporaneously from the patient.

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

iteratively access pairs of cardiac signals from a plurality of cardiac signals obtained from the patient, each pair having a first cardiac signal and different second cardiac signal;

process and assign for each of the pairs to define multiple cardiac activations in the first cardiac signal in each of the pairs;

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.

33. The system of claim 32, wherein the at least one computing device is further to display the cardiac activation pattern as reconstructed to facilitate treatment of cardiac tissue at the source to treat the cardiac rhythm disorder.