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• Determination of the end of the T wave for each channel
  In analogy with the determination of the start of the QRS complex, search is made towards the right on the basis of the maximum or minimum of the T wave, until the ECG merges with the isoelectric line. The end of the T wave is defined as the point in the ECG that has the largest distance to a straight line defined by 2 points: the first point lies on the isoelectric line behind the point in time when the ECG merges with the isoelectric line. The second point lies above the T wave maximum or below the T wave minimum.

4. QTc -

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The heart rate-corrected QT interval

As the QT interval depends on the heart rate - with high heart rate the QT interval is shorter and vice versa - a heart rate-adjusted, standardised QT interval is used for diagnostics, the so-called QTc interval. The QTc value shows which value the measured QT interval would have if it had been determined at a heart rate of 60/min, i.e. a R-R interval of 1s.
In custo diagnostic, the formulas according to Bazett and Fridericia are used.

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