What does the QT interval on an ECG represent?

The QT interval on an ECG represents the duration of both ventricular depolarization and repolarization. This measurement takes into account the time it takes for the ventricles to contract (depolarize) and then relax (repolarize) after each heartbeat. A prolonged or shortened QT interval can indicate potential issues related to the heart's electrical system, which may lead to arrhythmias if the interval is not within a normal range.

The importance of understanding the QT interval lies in its implications for cardiac health. If the QT interval is prolonged, it can increase the risk of dangerous arrhythmias such as Torsades de Pointes. Therefore, accurately measuring and interpreting the QT interval is crucial for assessing the electrical stability of the heart during an ECG evaluation. This aspect of cardiac physiology is essential for cardiographic technicians as they monitor and interpret various cardiac rhythms and conditions.