If the T wave ends past the halfway point of the RR interval, it is prolonged. Due to the effects of heart rate, the corrected QT interval (QTc) is frequently used. The QTc is considered prolonged if greater than 450 ms in males and 470 ms in females.
What does the QTc interval represent?
QT or QTc intervals that are long suggest abnormal effects on the myocardium. QT prolongation is usually divided into two categories, congenital and acquired. Congenital QT prolongation is an inherited disorder which places these people at increased risk of sudden death usually as children or young adults.
What is the QTc interval on an ECG?
A corrected QT interval (QTc) corrects for the variations in heart rate. QTcb is the QT interval divided by the square root of the RR interval in seconds when using the Bazett formula. The normal value of for QTcb in men is 0.44 seconds or less; in women, it is 0.46 seconds or less.
