Heart Electrical Cycle Interval

Calculator of QT Correction


What’s The QT Interval?

In order to use the QT Interval Calculator, we need to know what QT Interval even is. The QT Interval is an electrocardiographic visualization of the heart’s electrical function. This basically starts at the beginning of the QRS Complex and ends at the T Wave. In other words, it is caused by the depolarization of the ventricles and ends at the repolarization of the ventricles.

Who Uses The QT Interval?

You might be wondering who uses the QT Interval? This is used by cardiologists as it is directly related to the Torsades De Pointes. It is also a huge risk factor as it is related to cardiac death. If the heart rhythm is fast then the QT Interval is going to be short. That is when the QT Interval has to be corrected.

Bazett’s Formula:

Bazett’s Formula is an equation used all over the world for the correction of the QT Interval.
(QT corrected) =QT (sec) / sqrt(R-R Interval )
QTC= Corrected QT Interval
QT= QT Interval Duration
RR= Duration of RR Interval
Although, there is criticism involved with Bazett’s formula. Sometimes it can overcorrect at higher heart rates and undercorrect at lower heart rates. There are some other formulas that you can use to find the corrected QT Interval.

Framingham Correction:


M Hodges Equation:

QTc=QT+1.75(Heart Rate-60)

How To Use The Calculator?

Using our calculator to find the Corrected QT Interval is very easy, just follow the steps mentioned.

Step 1: Enter The Measured QT

In the first step of the process, we have to enter the Measured QT.

Step 2: Enter The RR Interval

Here, you have to enter the RR Interval that you measured.

What Will Be The Results?

Upon entering all the required information, you will be given a corrected QT Interval. A normal QT Interval after correction, 430ms for males and 450ms for females. If we talk about the QT Prolongation, then it would be over 450ms for males and 470ms for females.

Factors Affecting The QT Prolongation

Some of the main factors that create the QT Prolongation are:
  • Some Genetic Disorders, like the Romano Ward Syndrome
  • Hypokalemia- Very Low Blood Potassium
  • Various Heart Diseases
  • Hypocalcemia- Very Low Blood Calcium
  • Low Body Temperature¬†