QT INTERVAL MONITORING SYSTEM WITH ALARMS AND TRENDING

• US 20110092838A1
• Filed: 09/05/2008
• Published: 04/21/2011
• Est. Priority Date: 09/12/2007
• Status: Active Grant

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Mutch, Nancy, Lindauer, James E., Egan, Kathryn A, Babaeizadeh, Saeed, Gregg, Richard E, Michaud, Francis P, Kresge, Scott, Helfenbein, Eric, Wilm, Bernd, Zhou, Sophia Huai
• Granted Patent: US 9,538,933 B2
• Time in Patent Office: Days
• US Class Current: 600/516
• CPC Class Codes: A61B 5/349 Detecting specific parameters of the electrocardiograph cycle
• CPC Class Codes: A61B 5/364 Detecting abnormal ECG interval, e.g. extrasystoles, ectopic heartbeats

Abstract

An ECG monitoring system continuously monitors a patient'"'"'s ECG waveform and periodically identifies the patient'"'"'s QT interval. QT interval values are averaged over time and a corrected interval value QTc and a change in QTc relative to a baseline, dQTc, are periodically produced. An alarm is responsive to updated QT interval values and issues an alarm whenever a selected QT value exceeds an alarm limit. The periodically produced QT interval values are stored and a trend display may be produced showing changes in the QT interval information over different periods of time. The trend display may selectively display the trend information either graphically or in tabular form.

Claims

1. An ECG system for monitoring QT interval information comprising:

a source of ECG signal information;

a QT interval processor responsive to ECG signal information which operates to produce QT interval information; and

a variably settable alarm, responsive to the QT interval information, which issues an alarm when an alarm limit of the variably settable alarm is exceeded.

2. The ECG system of claim 1, further comprising a QT interval correction processor, responsive to QT interval information, which produces QTc values corrected for patient heart rate.

3. The ECG system of claim 2, further comprising a QT interval variation processor, responsive to a QTc value, which produces dQTc values relative to a baseline QTc value.

4. The ECG system of claim 3, further comprising a user control operable for updating the baseline QTc value.

5. The ECG system of claim 3, wherein the variably settable alarm has alarm limits for one or more of the QT interval information, QTc values, or dQTc values.

6. The ECG system of claim 2, further comprising a user control operable for selecting the correction process of the QT interval correction processor.

7. The ECG system of claim 1, further comprising a user control operable for selecting one or more ECG leads which produce ECG signal information for the QT interval processor.

8. The ECG system of claim 1, further comprising an ECG strip recorder, responsive to the issuance of an alarm by the variably settable alarm, which automatically records an ECG strip around the time of the issuance of the alarm.

9. The ECG system of claim 8, further comprising a user operated alarm review display for recalling and displaying an ECG strip recorded around the time of the issuance of an alarm.

10. The ECG system of claim 9, wherein the user operated alarm review display is operable to display alarm information both graphically and in tabular form.

11. An ECG system for monitoring QT interval information comprising:

a source of ECG signal information;

a QT interval processor responsive to ECG signal information which operates to periodically produce QT interval information;

a storage device responsive to the QT interval processor which stores QT interval information as a function of time; and

a display responsive to stored QT interval information and operable to display recalled QT interval information as a function of time.

12. The ECG system of claim 11, wherein the source of ECG signal information provides heartbeat signals for a plurality of ECG leads,

wherein the QT interval processor is responsive to the signals of a plurality of ECG leads for producing QT and/or QTc interval information at a first rate.

13. The ECG system of claim 12, wherein the first rate is once per minute.

14. The ECG system of claim 12, wherein the QT interval processor is responsive to the QT interval information for producing QT and/or corrected QT interval information at a second rate.

15. The ECG system of claim 14, wherein the QT interval processor produces a QT and/or QTc value every five minutes.

16. The ECG system of claim 15, further comprising a user control operable for selecting the correction process of the QT interval processor.

17. The ECG system of claim 11, wherein the display is selectably operable to display recalled QT interval information graphically or in tabular form.

18. The ECG system of claim 11, wherein the display is operable to display recalled QT interval information graphically;

and

further comprising a user operable cursor for selecting a particular time position of a graphical QT interval display,

wherein the display is further operable to display quantized values of QT interval information for a selected time position.

19. The ECG system of claim 18, wherein the QT interval information comprises two or more of the QT interval, QTc values, dQTc values or heart rate.

20. An ECG system for monitoring QT interval information comprising:

a source of ECG signal information;

a QT interval processor responsive to ECG signal information which operates to periodically produce QT interval information;

a storage device responsive to the QT interval processor which stores QT interval information as a function of time;

a trend processor, responsive to QT interval information which operates to calculate the trend of QT information over a period of time; and

a display responsive to the trend processor and operable to display a trend of QT information over the period of time.

21. The ECG system of claim 20, wherein the display displays the trend of QT information graphically.

22. The ECG system of claim 20, wherein the display displays the trend of QT information in tabular form.

23. The ECG system of claim 20 further comprising a user control operable to select the period of time over which the trend of QT information is displayed.

24. The ECG system of claim 20, wherein the QT interval information which is trended further comprises one or more of the QT interval, QTc values, dQTc values or heart rate.

25. The ECG system of claim 21, further comprising a user operable cursor which can be positioned over a graphical trend display,

wherein the display is further responsive to the positioning of the cursor for displaying quantized values of QT information relating to the time position of the cursor.