Medical devices for mapping cardiac tissue

• US 9,763,625 B2
• Filed: 05/06/2015
• Issued: 09/19/2017
• Est. Priority Date: 05/09/2014
• Status: Active Grant

• Current Assignee: Boston Scientific Scimed (Boston Scientific Corporation)
• Original Assignee: Boston Scientific Scimed (Boston Scientific Corporation)
• Inventors: Laughner, Jacob I., Shome, Shibaji, Thakur, Pramodsingh Hirasingh, Meyer, Scott A.
• Primary Examiner(s): WEHRHEIM, LINDSEY GAIL
• Application Number:
  US14/705,395
• Publication Number:
  US 20160007932A1
• Time in Patent Office: 867 Days
• CPC Class Codes: A61B 18/1492 having a flexible, catheter-like structure, e.g. for heart ablation A61B18/1477 takes precedence
• CPC Class Codes: A61B 2018/00577 Ablation
• 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 5/339 Displays specially adapted therefor
• CPC Class Codes: A61B 5/6858 with a distal basket, e.g. expandable basket
• CPC Class Codes: A61B 5/725 using specific filters therefor, e.g. Kalman or adaptive filters A61B5/316 take precedence
• CPC Class Codes: A61B 5/7253 characterised by using transforms
• CPC Class Codes: A61B 5/7257 using Fourier transforms
• CPC Class Codes: A61B 5/7278 Artificial waveform generation or derivation, e.g. synthesising signals from measured signals A61B5/327 takes precedence

Abstract

Medical devices and methods for making and using medical devices are disclosed. An example method may include a method of mapping the electrical activity of a heart. The method may include sensing a plurality of signals with a plurality of electrodes positioned within the heart, determining a dominant frequency of the plurality of signals and generating an alternate signal for each of the plurality of signals corresponding to the dominant frequency. The alternate signals may have a phase-shift corresponding to one of the plurality of signals. The method may also include displaying a characteristic of the alternate signal over time.

Claims

1. A method of using a system to map electrical activity of a heart, the system comprising (1) a mapping probe having a plurality of electrodes disposed at a distal end of the mapping probe, (2) a processing system, wherein each electrode of the plurality of electrodes is electrically coupled to the processing system, and (3) a display device coupled to the processing system, the method comprising:

sensing a plurality of signals with the plurality of electrodes positioned within the heart;

determining, by the processing system, a dominant frequency of the plurality of signals;

generating, by the processing system, an alternate signal for each of the plurality of signals corresponding to the dominant frequency, wherein each of the alternate signals has a phase-shift corresponding to one of the plurality of signals;

determining, by the processing system, an activation time corresponding to each of the plurality of signals, wherein determining the activation time corresponding to each of the plurality of signals comprises, for a first signal of the plurality of signals and a corresponding first alternate signal;

determining a first time, the first time comprising a time at which a characteristic of the alternate signal occurs;

creating a window of time around the first time;

determining a second time, the second time comprising a time at which a characteristic of the first signal occurs;

determining that the second time occurs within the window of time; and

selecting, in response to determining that the second time occurs within the window of time, the second time as the activation time corresponding to the first signal;

generating, based on the determined activation times, an activation map; and

displaying, by the processing system and on the display device, the activation map.

2. The method of claim 1, wherein determining a dominant frequency comprises:

processing each of the plurality of signals using a Fourier Transform;

generating a composite signal based on the processed plurality of signals;

identifying the frequency with the maximum power in the composite signal.

3. The method of claim 2, further comprising band-pass filtering each of the processed plurality of signals.

4. The method of claim 3, wherein the band-pass filtering comprises passing data in the 3 to 7 Hz band for each of the processed plurality of signals.

5. The method of claim 2, wherein generating the composite signal based on the processed plurality of signals comprises:

generating the composite signal with a value at each frequency that is one of a median value, a mean value, or a mode value of the processed plurality of signals at each frequency.

6. The method of claim 5, wherein the phase-shift of the alternate signals are based on the composite signal.

7. The method of claim 6, wherein each alternate signal is a sinusoid.

8. The method of claim 7, wherein each alternate signal is an analytic representation of a sinusoid.

9. The method of claim 8, wherein the analytic representation is generated by a Hilbert transform.

10. The method of claim 8, wherein the analytic representation is a sawtooth.

11. The method of claim 7, further comprising determining a fiducial point on each alternate signal, and wherein the fiducial point on each alternate signal is one of the following:

a point with a maximum negative derivative;

a point of zero-crossing; and

a point at phase π

/2.

12. The method of claim 11, further comprising determining an activation time for each of the plurality of signals based on the identified fiducial points, generating an activation map based on the determined activation times for each of the plurality of signals, and displaying the activation map.

13. A system for mapping the electrical activity of the heart, the system comprising:

a catheter shaft;

a plurality of electrodes coupled to the catheter shaft, the plurality of electrodes configured to sense a plurality of cardiac signals; and

a processor coupled to the catheter shaft, wherein the processor is configured to;

receive the plurality of signals sensed by the plurality of electrodes;

determine a dominant frequency of the plurality of signals;

generate an alternate signal for each of the plurality of signals corresponding to the dominant frequency, wherein each of the alternate signals has a phase-shift corresponding to one of the plurality of signals;

determine an activation time corresponding to each of the plurality of signals, wherein to determine the activation time corresponding to each of the plurality of signals comprises, for a first signal of the plurality of signals and a corresponding first alternate signal;

determine a first time comprising a time at which a characteristic of the alternate signal occurs;

create a window of time around the first time;

determine a second time comprising a time at which a characteristic of the first signal occurs;

determine that the second time occurs within the window of time; and

select the second time as the activation time corresponding to the first signal in response to determining that the second time occurs within the window of time;

generate an activation map based on the determined activation times; and

displaying the activation map.

14. The system of claim 13, wherein to determine a dominant frequency of the plurality of signals, the processor is further configured to:

transform each of the plurality of signals into the frequency domain;

generate a composite signal from each of the transformed plurality of signals; and

identify the frequency that has the maximum power in the composite signal.

15. The system of claim 13, wherein each alternate signal is an analytic representation of a sinusoid.

16. The system of claim 15, wherein the analytic representation is a sawtooth.