Understanding the QT Interval and QT Interval Correction
A Guide to Interpreting ECG Readings The QT interval is a measurement of the time it takes for the heart to electrically depolarize and repolarize. It is measured from the beginning of the QRS complex to the end of the T wave on an electrocardiogram (ECG). A prolonged QT interval can be dangerous and can lead to a type of arrhythmia called torsades de pointes, which can be fatal. The QT interval is affected by heart rate, so it is important to correct it for heart rate when interpreting an ECG....