ECG Rhythym Advisory Method

• US 20140236030A1
• Filed: 04/24/2014
• Published: 08/21/2014
• Est. Priority Date: 05/12/2004
• Status: Active Grant

• Current Assignee: Zoll Medical Corporation (Asahi Kasei Corporation)
• Original Assignee: Zoll Medical Corporation (Asahi Kasei Corporation)
• Inventors: Tan, Qing, Freeman, Gary A., Geheb, Frederick J., Brewer, James E.
• Granted Patent: US 9,642,547 B2
• Time in Patent Office: Days
• US Class Current: 600/509
• CPC Class Codes: A61B 5/347 Detecting the frequency distribution of signals
• CPC Class Codes: A61B 5/361 Detecting fibrillation
• CPC Class Codes: A61B 5/363 Detecting tachycardia or bradycardia
• CPC Class Codes: A61B 5/4839 combined with drug delivery
• CPC Class Codes: A61B 5/7207 of noise induced by motion artifacts
• CPC Class Codes: A61B 5/7257 using Fourier transforms
• CPC Class Codes: A61B 5/726 using Wavelet transforms
• CPC Class Codes: A61H 2201/5015 using specific interfaces or standards, e.g. USB, serial, parallel
• CPC Class Codes: A61H 2230/04 Heartbeat characteristics, e.g. E.G.C., blood pressure modulation
• CPC Class Codes: A61H 31/005 with feedback for the user
• CPC Class Codes: A61N 1/39 Heart defibrillators
• CPC Class Codes: A61N 1/3904 External heart defibrillators [EHD]
• CPC Class Codes: A61N 1/39044 in combination with cardiopulmonary resuscitation [CPR] therapy
• CPC Class Codes: A61N 1/3925 Monitoring; Protecting

Abstract

A method of automatically determining which type of treatment is most appropriate for a cardiac arrest victim, the method comprising transforming one or more time domain electrocardiogram (ECG) signals into a frequency domain representation comprising a plurality of discrete frequency bands, combining the discrete frequency bands into a plurality of analysis bands, wherein there are fewer analysis bands than discrete frequency bands,

• • determining the content of the analysis bands, and determining the type of treatment based on the content of the analysis bands.

Claims

1. A method of automatically determining which type of treatment is most appropriate for a cardiac arrest victim, the method comprising:

transforming one or more time domain electrocardiogram (ECG) signals into a frequency domain representation comprising a plurality of discrete frequency bands;

combining the discrete frequency bands into a plurality of analysis bands, wherein there are fewer analysis bands than discrete frequency bands;

determining the content of the analysis bands; and

determining the type of treatment based on the content of the analysis bands.

2. The method of claim 1 wherein transforming comprises the Fourier transform.

3. The method of claim 1 wherein transforming comprises a Wavelet transform.

4. The method of claim 1 wherein transforming comprises a Radon transform.

5. The method of claim 1 wherein determining the content of the analysis bands comprises determining a plurality of values.

6. The method of claim 5 wherein the content and the plurality of values are calculated at more than two points in time, and wherein the sequence of plurality of values in time defines a trajectory.

7. The method of claim 6 wherein the trajectory is analyzed using estimation and prediction methods.

8. The method of claim 7 wherein the analysis method involves use of a recursive filter.

9. The method of claim 8 wherein the recursive filter is a Kalman filter.

10. The method of claim 8 wherein the analysis method involves use of a Particle Filter.

11. The method of claim 7 wherein the analysis of the trajectory is used to predict defibrillation success.

12. The method of claim 7 wherein the analysis of the trajectory is used to determine whether it is appropriate to defibrillate or deliver an alternative therapy such as chest compressions, drugs such as epinephrine, constitutive nutrients such as glucose, or other electrical therapy such as pacing.

13. The method of claim 7 wherein a mathematical transformation is performed on the trajectory.

14. The method of claim 13 wherein the transformation is a projection of the trajectory onto a plane within the parameter space.

15. The method of claim 14 wherein image mensuration algorithms are employed to evaluate the features of the two dimensional projection of the trajectory.

16. The method of claim 1 wherein the content comprises at least two parameters descriptive of the content of an analysis band from the analysis bands.

17. The method of claim 1 wherein determining the content of an analysis band comprises quantifying the energy within an analysis band.

18. The method of claim 17 wherein quantifying the energy within an analysis band comprises determining at least one number characterizing the energy of the highest peak within the band.

19. The method of claim 17 wherein quantifying the energy with an analysis band comprises determining an overall or average energy for the band.

20. The method of claim 1 further comprising analyzing the variation over time of the content of the analysis bands.

21. The method of claim 1 wherein the bands are about 0.5 Hz in width.

22. The method of claim 1 wherein the bands are of unequal widths such that additional resolution is provided for frequency bands that are of greater importance in the analysis.

23. The method of claim 22 wherein frequencies less than 3 Hz are subdivided into bands whose widths are larger than those in the 6-12 Hz frequency range.

24. The method of claim 1 wherein each band is composed of an aggregation of multiple spectral measurements.

25. The method of claim 24 wherein characteristics of the distribution of spectral measurements within the band include at least one of the following descriptors:

mean spectral energy, spectral energy variance, median spectral energy, maximum spectral energy, or minimum spectral energy.