How does the "QT interval" change with heart rate?

The QT interval represents the time it takes for the ventricles to depolarize and then repolarize during each heartbeat. As the heart rate increases, the duration of the QT interval typically shortens. This is because faster heart rates allow less time for repolarization between beats. The body compensates for the increased frequency of heart contractions by adjusting the repolarization process, resulting in a shorter QT interval. This relationship helps maintain proper cardiac function, allowing for efficient filling and pumping of the heart under conditions of elevated demand, such as during exercise or stress.