As a medical professional with expertise in cardiology, I can provide you with information regarding the QTc interval, which is a heart rate-adjusted measure of the time between the start of the Q wave and the end of the T wave in the heart's electrical cycle. The upper limits of normal for the QTc are generally considered to be around 450 milliseconds (ms) for males and 470 milliseconds (ms) for females. It's important to note that these values can vary slightly depending on the specific criteria used by different clinical laboratories or medical guidelines. To estimate the upper limits of the QT interval itself, you can use the following approximation: at a heart rate of 60 beats per minute (bpm), the QT interval is roughly equal to the QTc. For every increase of 10 bpm in the heart rate, you would subtract 0.02 seconds from the QT interval. Please remember that these are general guidelines and individual patient circumstances can affect the interpretation of these values. It's always best to consult with a healthcare provider for a comprehensive evaluation. read more >>

An "abnormal" QTc in males is a QTc above 450 ms; and, in females, above 470 ms. If there is not a very high or low heart rate, the upper limits of QT can roughly be estimated by taking QT=QTc at a heart rate of 60 beats per minute (bpm), and subtracting 0.02s from QT for every 10 bpm increase in heart rate.read more >>