Corrected QT Interval (QTc) Calculator
Corrected QT Interval (QTc) Calculator.
Corrected QTc Calculator
What does QTc stand for?
The QT interval measures the duration between complete ventricular repolarization and depolarization. Various factors, including heart rate, nerve tone, electrolytes, and medications, influence its duration. Correcting the QT interval helps assess heart health and identify risks such as arrhythmia.
Normal Range for QTc
Normal QTc ranges from 0.33 to 0.44 seconds. A QT interval above 0.44 seconds may indicate myocardial instability. Values above 500ms are considered prolonged and can indicate arrhythmia risks.
QTc Bazett Formula
Formula: QTc = QT / √RR
Commonly used but may overcorrect or undercorrect depending on heart rate.
QTc Fredericia Formula
Formula: QTc = QT / RR1/3
Often used for better correction at extreme heart rates.
QTc Framingham Formula
Formula: QTc = QT + 0.154 * (1 - RR)
Developed using data from the Framingham Heart Study.
QTc Hodges Formula
Formula: QTc = QT + 0.00175 * (HR - 60)
A linear correction method considering heart rate variations.
How to Calculate QTc?
- For Bazett: QTc = QT / √RR
- For Fredericia: QTc = QT / RR1/3
- For Framingham: QTc = QT + 0.154 * (1 - RR)
- For Hodges: QTc = QT + 0.00175 * (HR - 60)