ECG rhythm advisory method

• US 7,831,299 B2
• Filed: 05/09/2006
• Issued: 11/09/2010
• Est. Priority Date: 05/12/2004
• Status: Expired due to Fees

• Current Assignee: Zoll Medical Corporation (Asahi Kasei Corporation)
• Original Assignee: Zoll Medical Corporation (Asahi Kasei Corporation)
• Inventors: Freeman, Gary A., Tan, Qing, Brewer, James E., Geheb, Frederick
• Primary Examiner(s): Layno; Carl H
• Assistant Examiner(s): Gedeon; Brian T
• Application Number:
  US11/430,579
• Publication Number:
  US 20060235320A1
• Time in Patent Office: 1,645 Days
• Field of Search: 600/508, 600/509
• 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 patient, the method comprising:

transforming a time domain electrocardiogram (ECG) signal from the patient into frequency domain data;

processing the frequency domain data to determine the variance of the energy distributed across a selected frequency range relative to a reference frequency of the spectrum of the ECG signal; and

determining the type of treatment based on the determined variance.

2. The method of claim 1 wherein the reference frequency comprises one of the following:

mean frequency, median frequency, center frequency, peak frequency.

3. The method of claim 1 further comprising providing a prompt to a user of the result of the determination of which type of treatment is most appropriate.

4. The method of claim 1 wherein determining the type of treatment based on the determined variance comprises comparing the determined variance to a threshold.

5. The method of claim 1 wherein determining the type of treatment based on the determined variance comprises combining the determined variance with one or more of the following in a multidimensional space:

a number of peaks in the selected frequency range;

relative values of multiple peaks in the selected frequency range; and

relative bandwidths of multiple peaks in the selected frequency range.

6. The method of claim 1 wherein the selected frequency range excludes a low-frequency portion in which a chest compression artifact dominates.

7. The method of claim 1 wherein variance is determined by computing the weighted distance of each frequency component from the reference frequency.

8. The method of claim 7 wherein the weighted distance of a given frequency component from the reference frequency comprises a squared difference between the given frequency component and the reference frequency multiplied by a magnitude of the frequency domain data at the given frequency component.

9. The method of claim 7 wherein the variance is determined by integrating the computed weighted distances over the selected frequency range.