Methods and Apparatuses for Determining a QT Interval of an ECG Signal
AssigneeBIOTRONIK SE & Co. KG
InventorsSwetha Vennelaganti, Ravi Kiran Kondama Reddy, R. Hollis Whittington
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Abstract
The disclosure relates to a method for determining a QT interval of an electrocardiogram (ECG) signal comprising the steps of: determining a QT interval of an electrocardiogram (ECG) signal comprising the steps of: determining a maximum slope of the ECG signal after a T wave maximum of the ECG signal, and fixing an end of the QT interval by performing, for example, extrapolating the maximum slope to a zero line of the ECG signal.
Claims15
A method for determining a QT interval of an electrocardiogram (ECG) signal, comprising the steps:
- determining a maximum slope of the ECG signal after a T wave maximum of the ECG signal;
- and
- fixing an end of the QT interval at least in part based on performing at least one of:
- extrapolating the maximum slope to a zero line of the ECG signal;
- determining a time position of the ECG signal after the T wave maximum at which the slope of the ECG signal is for the first time within a range of 70% to 20%, preferably 66% to 25%, of the maximum slope;
- determining a time position at which an absolute value of a difference of the ECG signal and a product of the maximum slope and a length of a time interval which is used for determining the maximum slope is below a predetermined threshold;
- calculating a second derivative of the ECG signal to determine an inflection point after the time position of the maximum slope-which is closest to the time position of the maximum slope.
A method for determining a QT interval of an electrocardiogram (ECG) signal, the method comprising the steps:
- searching for a zero slope of the ECG signal after a T wave maximum of the ECG signal;
- and
- fixing an end of the QT interval of the ECG signal at least in part based on determining a time position of a first zero slope of the ECG signal.
An apparatus for monitoring a QT interval of an electrocardiogram (ECG) signal comprising:
- a processor operable to:
- determine a maximum slope of the ECG signal after a T wave maximum of the ECG signal;
- and
- fix an end of the QT interval based at least in part on performing at least one of:
- extrapolate the maximum slope to a zero line of the ECG signal for fixing an end of the QT interval;
- determine a time position of the ECG signal after the T wave maximum at which the slope is for the first time within a range of 70% to 20%, preferred 66% to 25% of the maximum slope;
- determine a time position at which an absolute value of a difference of the ECG signal and a product of the maximum slope and a length of a time interval which is used for determining the maximum slope is below a predetermined threshold;
- calculate a second derivative of the ECG signal to determine an inflection point which is closest to the time position of the maximum slope.
An apparatus for monitoring a QT interval of an electrocardiogram (ECG) signal comprising:
- a processor operable to:
- search for a zero slope of the ECG signal after a T wave maximum of the ECG signal;
- and
- fix an end of the QT interval of the ECG signal at least in part based on determining a time position of a first zero slope of the ECG signal.
Dependencies are inferred from the claim text.