QT interval monitoring system with alarms and trending
First Claim
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.
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Accused Products
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.
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Citations
12 Claims
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1. An ECG system for monitoring QT interval information comprising:
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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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An ECG system for monitoring QT interval information, the system comprising:
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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. - View Dependent Claims (11, 12)
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Specification