SELECTION OF OPTIMAL CHANNEL FOR RATE DETERMINATION

• US 20160317059A1
• Filed: 07/08/2016
• Published: 11/03/2016
• Est. Priority Date: 03/25/2011
• Status: Active Grant

• Current Assignee: Zoll Medical Corporation (Asahi Kasei Corporation)
• Original Assignee: Zoll Medical Corporation (Asahi Kasei Corporation)
• Inventors: Volpe, Shane S., Kaib, Thomas E.
• Granted Patent: US 10,219,717 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61B 2560/0214 of power generation or supply
• CPC Class Codes: A61B 2560/0266 for monitoring or limiting apparatus function
• CPC Class Codes: A61B 2562/17 Comprising radiolucent components
• CPC Class Codes: A61B 5/0006 ECG or EEG signals
• CPC Class Codes: A61B 5/0245 by using sensing means generating electric signals, i.e. ECG signals
• CPC Class Codes: A61B 5/282 Holders for multiple electrodes for introduction into the body A61B5/287
• CPC Class Codes: A61B 5/304 Switching circuits
• CPC Class Codes: A61B 5/316 Modalities, i.e. specific diagnostic methods
• CPC Class Codes: A61B 5/333 Recording apparatus specially adapted therefor
• CPC Class Codes: A61B 5/341 Vectorcardiography [VCG]
• CPC Class Codes: A61B 5/35 by template matching
• CPC Class Codes: A61B 5/361 Detecting fibrillation
• CPC Class Codes: A61B 5/366 Detecting abnormal QRS complex, e.g. widening
• CPC Class Codes: A61B 5/4836 Diagnosis combined with treatment in closed-loop systems or methods A61B5/0036 takes precedence
• CPC Class Codes: A61B 5/6801 specially adapted to be attached to or worn on the body surface
• CPC Class Codes: A61B 5/6804 Garments; Clothes
• CPC Class Codes: A61B 5/6805 Vests
• CPC Class Codes: A61B 5/7221 Determining signal validity, reliability or quality A61B5/7207 and A61B5/7217 take precedence
• CPC Class Codes: A61B 5/7475 User input or interface means, e.g. keyboard, pointing device, joystick
• CPC Class Codes: A61N 1/046 Specially adapted for shock therapy, e.g. defibrillation
• CPC Class Codes: A61N 1/0476 : Array electrodes (including any electrode arrangement with more than one electrode for at least one of the polarities)
• CPC Class Codes: A61N 1/0484 : Garment electrodes worn by the patient
• CPC Class Codes: A61N 1/3925 : Monitoring; Protecting

Abstract

According to at least one example, an ambulatory medical device is provided. The device includes a plurality of electrodes disposed at spaced apart positions about a patient'"'"'s body and a control unit. The control unit includes a sensor interface, a memory and a processor. The sensor interface is coupled to the plurality of electrodes and configured to receive a first ECG signal from a first pairing of the plurality of electrodes and to receive a second ECG signal from a second pairing of the plurality of electrodes. The memory stores information indicating a preferred pairing, the preferred pairing being either the first pairing or the second pairing. The processor is coupled to the sensor interface and the memory and is configured to resolve conflicts between interpretations of first ECG signal and the second ECG signal in favor of the preferred pairing.

Claims

1. A medical device comprising:

at least one sensing electrode configured to be disposed on a patient;

a control unit comprising;

a sensor interface coupled to the at least one sensing electrode and configured to receive at least one electrocardiogram (ECG) signal from the at least one sensing electrode;

a memory storing a configurable parameter indicating at least one preferred heart rate detection method;

at least one processor coupled to the sensor interface and the memory, the least one processor being configured to implement a cardiac function analyzer to process the at least one ECG signal to determine a heart rate of the patient using two or more heart rate detection methods, to identify a difference in the heart rate of the patient as determined by the two or more heart rate detection methods, to retrieve the configurable parameter, and to resolve the difference in favor of the at least one preferred heart rate detection method.

2. The medical device of claim 1, wherein the medical device is ambulatory.

3. The medical device of claim 1, wherein the at least one preferred heart rate detection method has at least one refractory period that is different from a refractory period of a heart rate detection method of the two or more heart rate detection methods.

4. The medical device of claim 1, wherein the two or more heart rate detection methods comprise at least one of a QRS detector, a spectrum analyzer, and an axis analyzer.

5. The medical device of claim 1, wherein the cardiac function analyzer is further configured to identify automatically the at least one preferred heart rate detection method during operation of the medical device.

6. The medical device of claim 5, wherein the cardiac function analyzer is configured to identify the at least one preferred heart rate detection method by comparing at least one signal interpretation derived from the at least one preferred heart rate detection method to a benchmark.

7. The medical device of claim 6, wherein the benchmark comprises a signal interpretation of at least one of a normal cardiac rhythm and the patient'"'"'s cardiac rhythm.

8. The medical device of claim 7, wherein the patient'"'"'s cardiac rhythm is recorded during initial prescription and fitting of the medical device.

9. The medical device of claim 8, wherein the cardiac function analyzer is further configured to adjust the benchmark to match a composite ECG signal summarizing historical ECG signals of the patient.

10. The medical device of claim 9, wherein the historical ECG signals fall within a moving window of a predefined duration.

11. The medical device of claim 1, wherein the at least one sensing electrode comprises a plurality of sensing electrodes.

12. The medical device of claim 11, wherein the cardiac function analyzer is further configured to identify at least one of one or more pairings of the plurality of sensing electrodes and one or more refractory periods for the at least one preferred heart rate detection method.

13. The medical device of claim 12, wherein the cardiac function analyzer is further configured to adjust the one or more refractory periods to avoid differences due to abnormal T waves.

14. The medical device of claim 12, wherein the memory stores a plurality of patient profiles and the cardiac function analyzer is further configured to store, within a patient profile of the plurality of patient profiles, at least one of one or more indications of the one or more pairings, one or more indications of the one or more refractory periods, and the at least one preferred heart rate detection method.

15. The medical device of claim 12, further comprising a network interface configured to receive preference information descriptive of at least one of the one or more pairings, the one or more refractory periods, and the at least one preferred heart rate detection method.

16. The medical device of claim 1, wherein the at least one preferred heart rate detection method comprises a plurality of preferred heart rate detection methods and the cardiac function analyzer is configured to resolve the difference in favor of a highest ranking preferred heart rate detection method of the plurality of preferred heart rate detection methods.

17. The medical device of claim 1, wherein the at least one preferred heart rate detection method comprises a plurality of preferred heart rate detection method and the cardiac function analyzer is configured to resolve the difference in favor of a majority of the plurality of preferred heart rate detection methods.

18. A method of monitoring electrocardiogram (ECG) signals using a medical device comprising a memory and at least one sensing electrode, the method comprising:

storing, in the memory, a configurable parameter indicating at least one preferred heart rate detection method of a plurality of heart rate detection methods;

receiving at least one ECG signal via the at least one sensing electrode;

processing the at least one ECG signal to determine a heart rate of a patient using two or more heart rate detection methods of the plurality of heart rate detection methods;

detecting a difference in the heart rate as determined by the two or more heart rate detection methods; and

resolving the difference by retrieving the configurable parameter and resolving the difference in favor of the at least one preferred heart rate detection method.

19. The method of claim 18, wherein processing the at least one ECG signal comprises processing the at least one ECG signal using at least two of a QRS detector, a spectrum analyzer, and an axis analyzer.

20. A non-transitory computer readable medium storing sequences of instruction for monitoring electrocardiogram (ECG) signals comprising instructions configured to instruct at least one processor to:

store a configurable parameter indicating at least one preferred heart rate detection method of a plurality of heart rate detection methods;

receive at least one ECG signal via at least one sensing electrode;

process the at least one ECG signal to determine a heart rate of a patient using two or more heart rate detection methods of the plurality of heart rate detection methods;

detect a difference in the heart rate as determined by the two or more heart rate detection methods; and

resolve the difference by retrieving the configurable parameter and resolving the difference in favor of the at least one preferred heart rate detection method.

21. The computer readable medium of claim 20, wherein the instructions configured to instruct the at least one processor to process the at least one ECG signal comprise instructions configured to instruct the at least one processor to process the at least one ECG signal using at least two of a QRS detector, a spectrum analyzer, and an axis analyzer.

22. An ambulatory medical device comprising:

a plurality of electrodes disposed about a patient'"'"'s body; and

a control unit including;

a sensor interface coupled to the plurality of electrodes and configured to receive a plurality of electrocardiogram (ECG) signals from a plurality of pairings of the plurality of electrodes;

a memory storing a configurable parameter indicating at least one preferred pairing of the plurality of pairings; and

at least one processor coupled to the sensor interface and the memory, the least one processor implementing a cardiac function analyzer to process the plurality of ECG signals to detect heartbeats of the patient, to identify a difference in the heartbeats detected by two or more pairings of the plurality of pairings, to retrieve the configurable parameter, and to resolve the difference in favor of the at least one preferred pairing.

23. The ambulatory medical device of claim 22, wherein the cardiac function analyzer is further configured to identify at least one of one or more detection methods and one or more refractory periods for the at least one preferred pairing.

24. The ambulatory medical device of claim 23, wherein the cardiac function analyzer is further configured to adjust the one or more refractory periods to avoid differences due to abnormal T waves.

25. The ambulatory medical device of claim 23, wherein the one or more detection methods comprise at least one of a QRS detector, a spectrum analyzer, and an axis analyzer.

26. The ambulatory medical device of claim 22, wherein the at least one preferred pairing includes a plurality of preferred pairings and the cardiac function analyzer is configured to resolve the difference in favor of a highest ranking preferred pairing of the plurality of preferred pairings.

27. The ambulatory medical device of claim 22, wherein the at least one preferred pairing includes a plurality of preferred pairings and the cardiac function analyzer is configured to resolve the difference in favor of a majority of the plurality of preferred pairings.

28. An ambulatory medical device comprising:

a plurality of electrodes disposed about a patient'"'"'s body; and

a control unit including;

a sensor interface coupled to the plurality of electrodes and configured to receive a first electrocardiogram (ECG) signal from a first pairing of the plurality of electrodes and to receive a second ECG signal from a second pairing of the plurality of electrodes;

a memory configured to store a configurable parameter indicating at least one preferred pairing of the first pairing and the second pairing; and

at least one processor coupled to the sensor interface and the memory and configured to process the first ECG signal to determine a first signal interpretation of a physical condition of the patient, to process the second ECG signal to determine a second signal interpretation of the physical condition of the patient, to determine a first level of confidence in the first signal interpretation, to determine a second level of confidence in the second signal interpretation, to determine that the first level of confidence is higher than the second level of confidence, and to store an indicator of the first pairing in the configurable parameter.

29. The ambulatory medical device of claim 28, wherein the cardiac function analyzer is configured to:

determine the first level of confidence by comparing the first signal interpretation to a benchmark; and

determine the second level of confidence by comparing the first signal interpretation to the benchmark.

30. The ambulatory medical device of claim 29, wherein the benchmark includes a signal interpretation of at least one of a normal cardiac rhythm and the patient'"'"'s cardiac rhythm.

31. The ambulatory medical device of claim 30, wherein the patient'"'"'s cardiac rhythm is recorded during initial prescription and fitting of the ambulatory medical device.

32. The ambulatory medical device of claim 31, wherein the cardiac function analyzer is further configured to adjust the benchmark to match a composite ECG signal summarizing historical ECG signals of the patient.