Patent ID: 7627369

Claim:
A method of measuring a QT interval of an electrocardiogram (ECG) signal wherein an end of a T wave is identified from ECG data, the method comprising the steps of: (a) acquiring ECG signal data from a signal acquisition apparatus or from a data storage; (b) deriving a first set of ECG signal data from the acquired ECG signal data using an electronic system; (c) inverting the first set of ECG signal data to derive a second set of ECG signal data using the electronic system, said second set of ECG signal data comprising an inverted set of said first set of ECG signal data; and (d) determining the end of the T wave using the electronic system by reference to timing of at least one intersection at which an upright T wave of said first set of derived ECG signal data intersects an inverted T wave of a said second set of derived ECG signal data, the two sets of ECG data being superimposed so as to maximize data fit over a segment of ECG signal after a peak of the positive T wave.