LOCATING J-POINTS IN ELECTROCARDIOGRAM SIGNALS

• US 20170007144A1
• Filed: 06/30/2016
• Published: 01/12/2017
• Est. Priority Date: 07/09/2015
• Status: Active Grant

• Current Assignee: Dragerwerk AG & Company KGaA (FPS Vermögensverwaltung GmbH)
• Original Assignee: Draeger Medical Systems Incorporated (Dragerwerk AG)
• Inventors: Zhang, Zhe, Roset, Scott, Chen, Yu
• Granted Patent: US 10,188,305 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61B 5/282 Holders for multiple electrodes for introduction into the body A61B5/287
• CPC Class Codes: A61B 5/316 Modalities, i.e. specific diagnostic methods
• CPC Class Codes: A61B 5/349 Detecting specific parameters of the electrocardiograph cycle
• CPC Class Codes: A61B 5/7282 Event detection, e.g. detecting unique waveforms indicative of a medical condition A61B5/4094, A61B5/4818, A61B5/349, A61B5/0823 take precedence

Abstract

The current subject matter determines the location of the J-point in an ECG signal by examining ECG samples within a window of samples between the S-peak and the T-peak. The sample in this range with the smallest distance, Δd, to the R-peak is selected as the J-point. Thus, the J-point location can be determined based on an ECG sample'"'"'s distance to the R-peak. The J-point location can then be used to determine whether there is elevation or depression of the ST segment. Related apparatus, systems, techniques, and articles are also described.

Claims

1. A method for implementation by one or more data processors forming part of at least one computing device, the method comprising:

receiving electrocardiogram (ECG) data derived from an ECG electrode set affixed to a patient, the ECG data comprising a sequence of cardiac cycle waveforms that each correspond to a single cardiac cycle, each waveform comprising a series of samples;

locating, for each cardiac cycle waveform, an R-peak, an S-peak, and a T-peak;

identifying, for each cardiac cycle waveform, a sample within a window of samples between the S-peak and the T-peak that is closest in distance to the R-peak; and

providing, for each cardiac cycle waveform, data specifying a location of the identified sample as being a J-point for the corresponding cardiac cycle waveform.

2. The method of claim 1, further comprising:

calculating, for each cardiac cycle waveform, a midpoint sample between the S-peak and the T-peak;

wherein the window only includes samples between the S-peak and the midpoint sample.

3. The method of claim 1, further comprising:

identifying, for each cardiac cycle waveform, beginning of a T wave corresponding to the T-peak; and

measuring deviation of an ST segment starting at the J-point and terminating at the beginning of the T wave relative to a baseline, the ST segment corresponding to an interval between ventricular depolarization and repolarization of the patient.

4. The method of claim 3, wherein the baseline is a TP interval of the corresponding cardiac cycle waveform defined by the end of the T wave and start of a next P wave in the cardiac cycle waveform.

5. The method of claim 3, wherein the baseline is a PR interval of the corresponding cardiac cycle waveform defined by an end of a P wave and start of a QRS complex in the cardiac cycle waveform.

6. The method of claim 3, further comprising:

providing data characterizing the measured deviation of the ST segment.

7. The method of claim 6, wherein providing data characterizing the measured elevation of the ST segment comprises at least one of:

displaying at least a portion of the data on an electronic display, loading at least a portion of the data into memory, storing at least a portion of the data into persistent storage, or transmitting at least a portion of the data to a remote computing system.

8. The method of claim 3, wherein the measured deviation is an elevation of the ST segment relative to the baseline or a depression of the ST segment relative to the baseline.

9. The method of claim 1 further comprising:

scaling, prior to the calculating, each cardiac cycle waveform to a predetermined scale.

10. The method of claim 9, wherein the scaling applies equal weights to each axis of the cardiac cycle waveform.

11. The method of claim 9, wherein each cardiac cycle waveform is scaled such that, on an x-axis of the cardiac cycle waveform, the scaling is between the R-peak and the midpoint sample.

12. The method of claim 9, wherein each cardiac cycle waveform is scaled such that, on a y-axis of the cardiac cycle waveform, the scaling is between the R-peak and the S-peak.

13. The method of claim 1, wherein the identifying comprises:

calculating a distance of each sample between the R-peak and the midpoint sample, wherein the identified sample corresponds to the sample having the shortest distance from the R-peak.

14. The method of claim 1, wherein the identifying comprises:

calculating a distance of a subset of samples between the R-peak and the midpoint sample, wherein the identified sample corresponds to the sample having the shortest distance from the R-peak.

15. The method of claim 14, wherein at least a portion of the samples not forming part of the subset of samples are skipped such that a distance is not calculated for such samples.

16. The method of claim 14, wherein selection of samples for which distances are calculated are based on a characteristic of a sample for which a distance was previously calculated.

17. The method of claim 1, wherein the identifying comprises:

calculating, for each sample in sequential temporal order, a distance of the sample from the midpoint R-peak until the midpoint sample is reached, wherein the identified sample corresponds to the sample having the shortest distance from the R-peak.

18. The method of claim 1, wherein the identifying comprises:

calculating, for each sample in reverse sequential temporal order starting at the midpoint sample, a distance of the sample from the midpoint R-peak until the R-peak is reached, wherein the identified sample corresponds to the sample having the shortest distance from the R-peak.

19. The method of claim 1, wherein the providing data comprises at least one of:

displaying at least a portion of the data on an electronic display, loading at least a portion of the data into memory, storing at least a portion of the data into persistent storage, or transmitting at least a portion of the data to a remote computing system.

20. The method of claim 1, wherein at least one of the receiving, locating, calculating, identifying, or providing is executed by a patient monitor in communication with the ECG electrode set.

21. The method of claim 1, wherein the ECG data is continuously updated while the patient is being monitored.

22. A system comprising:

at least one data processor; and

memory storing instructions which, when executed by the at least one data processor, perform operations comprising;

receiving electrocardiogram (ECG) data derived from an ECG electrode set affixed to a patient, the ECG data comprising a sequence of cardiac cycle waveforms that each correspond to a single cardiac cycle, each waveform comprising a series of samples;

locating, for each cardiac cycle waveform, an R-peak, an S-peak, and a T-peak;

identifying, for each cardiac cycle waveform, a sample within a window of samples between the S-peak and the T-peak that is closest in distance to the R-peak; and

providing, for each cardiac cycle waveform, data specifying a location of the identified sample as being a J-point for the corresponding cardiac cycle waveform.

23. The system of claim 22 further comprising:

an electrocardiogram (ECG) electrode set for generating ECG signals when affixed to a patient.

24. The system of claim 23, wherein the at least one data processor and memory form part of a patient monitor, the patient monitor comprising an interface for communication with the ECG electrode set.

25. A non-transitory computer program product storing instructions which, when executed by at least one data processor forming part of at least one computing device, perform operations comprising:

receiving electrocardiogram (ECG) data derived from an ECG electrode set affixed to a patient, the ECG data comprising a sequence of cardiac cycle waveforms that each correspond to a single cardiac cycle, each waveform comprising a series of samples;

locating, for each cardiac cycle waveform, an R-peak, an S-peak, and a T-peak;

identifying, for each cardiac cycle waveform, a sample within a window of samples between the S-peak and the T-peak that is closest in distance to the R-peak; and

providing, for each cardiac cycle waveform, data specifying a location of the identified sample as being a J-point for the corresponding cardiac cycle waveform.