System and method for reconstructing cardiac activation information
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 identify 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. An activation onset time is assigned in the first cardiac signal at the point of change to define a cardiac activation.
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 identify 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; and
assigning an activation onset time in the first cardiac signal at the point of change to define a cardiac activation.
2. The method of claim 1 , wherein the point of change is associated with a largest divergence of the derivative of the first cardiac signal with respect to the derivative of the second cardiac signal.
3. 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.
4. 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.
5. 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.
6. 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.
7. 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.
8. The method of claim 7 , wherein the first cardiac signal and the second cardiac signal are obtained contemporaneously from the patient.
9. The method of claim 1 , wherein the point of change is identified at about the same time point for the first cardiac signal and the second cardiac signal.
10. The method of claim 1 , wherein the point of change is identified using one or more of slope, amplitude, timing and shape for the first cardiac signal and the second cardiac signal.
11. 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.
12. The method of claim 1 , wherein the point of change is higher than a noise level associated with the first cardiac signal and the second cardiac signal.
13. The method of claim 1 , further comprising accessing, processing and assigning to define multiple cardiac activations in the first cardiac signal.
14. The method of claim 1 , further comprising iteratively accessing the first cardiac signal and the second cardiac signal from a plurality of cardiac signals.
15. 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.
16. The method of claim 15 , further comprising displaying the cardiac activation pattern as reconstructed to facilitate treatment of cardiac tissue at the source to treat the cardiac rhythm disorder.
17. 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 identify 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; and
assign an activation onset time in the first cardiac signal at the point of change to define a cardiac activation.
18. The system of claim 17 , wherein the point of change is associated with a largest divergence of the derivative of the first cardiac signal with respect to the derivative of the second cardiac signal.
19. The system of claim 17 , 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 17 , 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 17 , 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 17 , 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 17 , 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 17 , wherein the point of change is identified at about the same time point for both the first cardiac signal and the second cardiac signal.
25. The system of claim 17 , wherein the point of change is identified using one or more of slope, amplitude, timing and shape for the first cardiac signal and the second cardiac signal.
26. The system of claim 17 , 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 17 , wherein the at least one computing device is further to access, process and assign to define multiple cardiac activations in the first cardiac signal.
28. The system of claim 17 , 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.
29. The system of claim 17 , 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.
30. The system of claim 29 , wherein the first cardiac signal and the second cardiac signal are obtained contemporaneously from the patient.
31. The system of claim 17 , 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.
32. The system of claim 31 , 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.