Corrected QT Interval Calculator
QTc (Bazett Formula)
Formula
QTc (Bazett) = QT / sqrt(RR) | QTc (Fridericia) = QT / RR^(1/3) | RR = 60 / HR
Frequently Asked Questions
What is the corrected QT interval?
QTc adjusts the QT interval for heart rate. The Bazett formula (QTc = QT / sqrt(RR)) is most widely used. Normal QTc is 350-450 ms in males and 350-470 ms in females.
What is a dangerous QTc?
QTc > 500 ms is associated with significantly increased risk of torsades de pointes and sudden cardiac death. QTc > 450 ms (male) or > 470 ms (female) is considered prolonged.
What causes prolonged QT?
Causes include medications (antiarrhythmics, antibiotics, antipsychotics), electrolyte imbalances (hypokalemia, hypomagnesemia), and congenital long QT syndrome.
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