QTc Bazett Formula Calculator

QTc Bazett Formula: Explanation and Clinical Context The QT interval represents the time from the start of ventricular depolarization to the end of ventricular repolarization on an electrocardiogram (ECG). QT interval duration varies with heart rate, and QTc (corrected QT) is calculated to standardize QT for heart rate. Bazett's formula is the most widely used correction: QTc = QT / √RR, where QT is in milliseconds and RR is in seconds (interval between two consecutive R waves).

Bazett correction is most accurate at normal heart rates but tends to overestimate QTc at high heart rates and underestimate at low heart rates. QTc prolongation is clinically significant as it may indicate an increased risk of torsades de pointes and sudden cardiac death. Normal reference values: men < 450 ms, women < 460 ms.

QTc > 500 ms is generally considered high risk.