Frequently Asked Questions
What is the difference between Bazett and Fridericia?
Bazett divides QT by the square root of the RR interval, while Fridericia uses the cube root. Fridericia is often more reliable at very high or very low heart rates because it over-corrects less.
When is a QTc considered prolonged?
A QTc of 480 milliseconds or more is generally considered prolonged, 450 to 480 is borderline, and below 450 is normal. Prolongation can raise the risk of arrhythmias.
Which QTc formula is most accurate?
Bazett's formula (QTc = QT / √RR) is the most widely used but over-corrects at high heart rates. Fridericia's formula (QTc = QT / ∛RR) performs better at tachycardia. Hodges and Framingham corrections are linear and handle a broader heart rate range with less bias. Most clinical guidelines and drug safety studies still reference Bazett, so results from other formulas should be noted when deviating from that standard.
Provided by AllCalculators.io
Free online calculators for everyday. No registration required.
General information only. Not medical advice.
Health & Medical Disclaimer: General information only. Not medical advice.
This calculator provides general health information only and is not medical advice. Results do not replace professional medical evaluation or diagnosis. Consult a licensed healthcare provider before making health decisions. Always seek immediate medical attention for emergencies.