System and method for reconstructing cardiac activation information

Patent metadata

Field	Value
Publication number	US-9468387-B2
Application number	US-201514724621-A
Country	US
Kind code	B2
Filing date	May 28, 2015
Priority date	May 2, 2011
Publication date	Oct 18, 2016
Grant date	Oct 18, 2016

Abstract

An example system and method of reconstructing cardiac activation information are disclosed. In accordance therewith, there are accessed pairs of cardiac signals out of a plurality of cardiac signals obtained from a patient. The pairs have a first cardiac signal that is common among the pairs and second cardiac signals that are different among the pairs. The first cardiac signal and the second cardiac signals of the pairs are processed to identify points of change in the first cardiac signal at which a derivative of the first cardiac signal diverges with respect to derivatives of the second cardiac signals. An activation onset time is assigned at a point in the first cardiac signal based on correspondence of the points of change to define a cardiac activation indicating a beat.

First claim

The invention claimed is:

1. A method of reconstructing cardiac activation information, the method comprising:
accessing, by a computing device, pairs of cardiac signals out of a plurality of cardiac signals obtained from a patient, the pairs having a first cardiac signal that is common among the pairs and second cardiac signals that are different among the pairs;
processing, by the computing device, the first cardiac signal and the second cardiac signals of the pairs to identify points of change in the first cardiac signal at which a derivative of the first cardiac signal diverges with respect to derivatives of the second cardiac signals;
determining, by the computing device, a correspondence among the points of change; and
assigning, by the computing device, an activation onset time at a point in the first cardiac signal based on the correspondence among the points of change to define a cardiac activation, wherein the cardiac activation indicates a beat in the first cardiac signal.

2. The method of claim 1 , wherein the points of change are associated with largest divergences of the derivative of the first cardiac signal with respect to the derivatives of the second cardiac signals.

3. The method of claim 1 , wherein the step of assigning further comprises averaging activation onset times associated with the points of change to determine the activation onset time of the point.

4. The method of claim 1 , wherein the step of assigning further comprises averaging selected activation onset times associated with the points of change to determine the activation onset time of the point, the selected activation onset times representing a majority of activation onset times associated with the points of change that are within a predetermined time interval of each other.

5. The method of claim 1 , wherein the step of assigning further comprises calculating a center-of-mass of activation onset times associated with the points of change weighted by their significance to determine the activation onset time of the point.

6. The method of claim 1 , wherein the step of assigning further comprises defining a predominant direction of activation onset times associated with the points of change relative to sensor locations to determine the activation onset time of the point.

7. The method of claim 1 , wherein the derivative of the first cardiac signal and the derivatives of the second cardiac signals 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.

8. The method of claim 1 , wherein the step of accessing comprises obtaining the first cardiac signal and the second cardiac signals from the patient using a first sensor and different second sensors, respectively.

9. The method of claim 8 , wherein the first cardiac signal and the second cardiac signals are obtained contemporaneously from the patient.

10. The method of claim 1 , wherein a point of change is identified at about the same time point for the first cardiac signal and a second cardiac signal of a pair.

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

12. The method of claim 1 , wherein identification of a point of change comprises:
forming a composite cardiac signal from the first cardiac signal and a second cardiac signal of a pair;
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 a point of change in the first cardiac signal a point having a largest ratio value from the determined ratio values.

13. The method of claim 1 , wherein the points of change are higher than a noise level associated with the first cardiac signal and the second cardiac signals of the pairs.

14. The method of claim 13 , wherein a point of change of a pair 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.

15. The method of claim 1 , wherein the method further comprises performing accessing, processing, determining, and assigning to define multiple cardiac activations indicating multiple beats in the first cardiac signal.

16. The method of claim 1 , wherein the method further comprises:
iteratively selecting first cardiac signals from the plurality of cardinal signals;
accessing pairs of cardiac signals out of the plurality of cardiac signals for each selected first cardiac signal, the pairs having the selected first cardiac signal that is common among the pairs and second cardiac signals that are different among the pairs;
performing processing and assigning for the pairs of cardiac signals associated with each selected first cardiac signal to define multiple cardiac activations indicating multiple beats in the selected first cardiac signals; 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 , wherein the method further comprises displaying the cardiac activation pattern as reconstructed to facilitate treatment of cardiac tissue at the source to suppress, lessen or eliminate the cardiac rhythm disorder.

18. A system to reconstruct cardiac activation information, the system comprising:
a computing device storing instructions that, when executed by the computing device, cause the computing device to perform operations comprising:
accessing pairs of cardiac signals out of a plurality of cardiac signals obtained from a patient, the pairs having a first cardiac signal that is common among the pairs and second cardiac signals that are different among the pairs;
processing the first cardiac signal and the second cardiac signals of the pairs to identify points of change in the first cardiac signal at which a derivative of the first cardiac signal diverges with respect to derivatives of the second cardiac signals;
determining a correspondence among the points of change; and
assigning an activation onset time at a point in the first cardiac signal based on the correspondence among the points of change to define a cardiac activation, wherein the cardiac activation indicates a beat in the first cardiac signal.

19. The system of claim 18 , wherein the points of change are associated with largest divergences of the derivative of the first cardiac signal with respect to the derivatives of the second cardiac signals.

20. The system of claim 18 , wherein the assigning operations further comprise averaging activation onset times associated with the points of change to determine the activation onset time of the point.

21. The system of claim 18 , wherein the assigning operations further comprise averaging selected activation onset times associated with the points of change to determine the activation onset time of the point, the selected activation onset times representing a majority of activation onset times associated with the points of change that are within a predetermined time interval of each other.

22. The syste

Assignees

• Univ California
• Topera Inc
• Us Veterans Affairs

Inventors

• Narayan Sanjiv
• Briggs Carey Robert

Classifications

• A61B5/742

  using visual displays (displays for heart-related electrical signals, e.g. ECG, A61B5/339) · CPC title

• A61B5/7203

  for noise prevention, reduction or removal · CPC title

• A61B5/7282

  Event detection, e.g. detecting unique waveforms indicative of a medical condition (cough events A61B5/0823; seizures A61B5/4094; sleep apnoea A61B5/4818) · CPC title

• A61B2562/046

  in a matrix array · CPC title

• A61B5/7278

  Artificial waveform generation or derivation, e.g. synthesizing signals from measured signals · CPC title