ECG Rhythm Advisory Method

• US 20070100379A1
• Filed: 12/07/2006
• Published: 05/03/2007
• 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, Geheb, Frederick, Brewer, James, Freeman, Gary
• Granted Patent: US 8,706,214 B2
• Time in Patent Office: Days
• US Class Current: 607/2
• 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 appropriate for a cardiac arrest victim, the method comprising:

measuring at least one physiological signal,

determining at least two parameters related to the at least one physiological signal, the at least two parameters forming a parameter set,

repeating the measurement and calculation at more than two points in time to create a sequence of parameter sets, wherein the sequence of parameter sets defines a trajectory; and

analyzing the trajectory using estimation and prediction methods that comprise the use of a recursive filter.

2. The method of claim 1 wherein the recursive filter is a Kalman filter.

3. The method of claim 1 wherein the analysis method involves use of a Particle filter.

4. The method of claim 1 wherein the analysis of the trajectory is used to predict defibrillation success.

5. The method of claim 1 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.

6. The method of claim 1 wherein a mathematical transformation is performed on the trajectory.

7. The method of claim 6 wherein the transformation is a projection of the trajectory onto a plane within the parameter space.

8. The method of claim 7 wherein image mensuration algorithms are employed to evaluate the features of the two dimensional projection of the trajectory.

9. The method of claim 2 or 3 wherein the predicted next state of the parameter set is used to determine the appropriate treatment.

10. The method of claim 1 wherein the method is carried out by a device configured to determine an appropriate therapy for a rescuer to perform on the victim.

11. The method of claim 1 wherein the probability of defibrillation success associated with a plurality of alternative treatments is shown on the display of the device.

12. The method of claim 11 wherein the probability of success with a plurality of treatments is shown on the display as range of numbers.

13. The method of claim 10 wherein the device is an AED that notifies the rescuer in the form of an audible or visual alarm indicating that the paramedic should stop doing compressions for a more accurate analysis of the ECG waveform.

14. The method of claim 10 wherein the device is an AED that notifies the rescuer in the form of an audible or visual alarm indicating that the paramedic should alter the therapy being delivered.