What is the normal range for the QT interval in adults?

The normal range for the QT interval in adults is typically between 0.35 to 0.45 seconds. The QT interval represents the time it takes for the heart's electrical system to reset itself after each heartbeat, and it is measured from the beginning of the Q wave to the end of the T wave on an electrocardiogram (ECG).

When assessing the QT interval, it's essential to consider that it can be influenced by factors such as heart rate, age, and gender. In clinical practice, the QT interval may also be corrected for heart rate (QTc) to standardize the measurement across different heart rates, as a faster heart rate can artificially shorten this interval.

Setting the normal range at 0.35 to 0.45 seconds helps clinicians identify potential abnormalities. A QT interval longer than this range may indicate a risk for arrhythmias, and a shortened QT interval can be associated with other cardiac or metabolic conditions.