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PR Interval
QRS Interval
QT Interval
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To determine the QT Interval.

The QT interval begins at the onset of the QRS complex and terminates at the end of the T wave. It represents the time of ventricular depolarization and repolarization. It is useful as a measure of repolarization and is influenced by electrolyte balance, drugs, and ischemia. The QT interval is inversely related to heart rate. A QT interval corrected for heart rate can be calculated.