QT interval monitoring system with alarms and trending

• US 9,538,933 B2
• Filed: 09/05/2008
• Issued: 01/10/2017
• Est. Priority Date: 09/12/2007
• Status: Active Grant

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips N.V.
• Inventors: Helfenbein, Eric, Zhou, Sophia Huai, Lindauer, James E., Gregg, Richard E, Kresge, Scott, Wilm, Bernd, Egan, Kathryn A, Mutch, Nancy, Babaeizadeh, Saeed, Michaud, Francis P
• Primary Examiner(s): Wu, Eugene T
• Application Number:
  US12/676,948
• Publication Number:
  US 20110092838A1
• Time in Patent Office: 3,049 Days
• Field of Search: 607/25, 600/515, 600/516, 600/518, 600/523
• US Class Current: 1/1
• 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 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 a trend of QT information over a period of time, wherein the QT interval information which is trended further includes one or more of the QT interval, QTc values, and dQTc values;

a QT interval correction processor which produces the QTc values corrected for a patient heart rate;

a QT interval variation processor which produces dQTc values relative to a baseline QTc value;

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

a user control operable to select the period of time over which the trend of QT information is displayed.

2. The ECG system of claim 1, wherein the display displays a variably settable alarm responsive to the QT interval information exceeding an alarm limit.

3. The ECG system according to claim 2, further including:

an ECG strip recorder which automatically records an ECG strip around the time of the issuance of the alarm.

4. The ECG system according to claim 3, further including:

a user operated alarm review display for recalling and displaying an ECG strip recorded around the time of the issuance of an alarm.

5. The ECG system according to claim 2, 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 1, wherein the display displays the trend of QT information graphically.

7. The ECG system of claim 6, further including:

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.

8. The ECG system of claim 1, wherein the display displays the trend of QT information in tabular form.

9. The ECG system according to claim 1, further including:

a user control operable for selecting one or more ECG leads which produce ECG signal information for the QT interval processor.

10. An ECG system for monitoring QT interval information, the system comprising:

a display device;

one or more processors programmed to;

identify QT intervals in a received ECG signal over a plurality of cardiac cycles,

calculate a QT trend line indicative of a change in the QT interval over a period of time,

determine heart rates from the ECG signal,

correct the identified QT intervals with the determined heart rates to generate corrected QT (QTc) intervals,

calculate a QTc trend line indicative of a change in the corrected QT interval over the period of time,

calculate a change in the corrected QT interval to generate a change in QTc (dQTc) intervals,

calculate a dQTc trend line indicative of a change in the dQTc interval over the period of time,

control the display device to display the ECG signal, QT trend line, QTc trend line, and dQTc trend line; and

a user input device by which a user selects the period of time.

11. The ECG system of claim 10, wherein a cursor controlled by the user input device slides a vertical cursor line along the trend lines.

12. The ECG system of claim 11, wherein specific values along the trend lines are displayed in response to the position of the Cursor.