1. What is Bazett's Formula?

Bazett's formula is used to calculate the corrected QT interval (QTc) which accounts for heart rate variations. It provides a standardized measure of ventricular repolarization that can be compared across different heart rates.

2. How Does the Calculator Work?

The calculator uses Bazett's formula:

Where:

• \( QT \) — QT interval measured from start of Q wave to end of T wave (ms)
• \( RR \) — RR interval calculated as 60 / HR (seconds)
• \( HR \) — Heart rate (beats per minute)

Explanation: The formula corrects the QT interval for heart rate by dividing by the square root of the RR interval.

3. Importance of QTc Calculation

Details: QTc calculation is essential for assessing cardiac repolarization abnormalities. Prolonged QTc intervals may indicate increased risk of ventricular arrhythmias and sudden cardiac death.

4. Using the Calculator

Tips: Enter QT interval in milliseconds and heart rate in beats per minute. Both values must be positive numbers. Normal QTc values are typically between 350-440 ms.

5. Frequently Asked Questions (FAQ)

Q1: What is a normal QTc value?
A: Normal QTc values are typically between 350-440 ms. Values above 440 ms in men or 460 ms in women may indicate prolonged QT interval.

Q2: Why is QTc correction important?
A: The QT interval naturally shortens with faster heart rates. Correction allows comparison of QT intervals across different heart rates.

Q3: Are there limitations to Bazett's formula?
A: Bazett's formula may overcorrect at high heart rates and undercorrect at low heart rates. Other formulas like Fridericia's may be used in specific cases.

Q4: When should QTc be measured?
A: QTc should be measured in patients taking medications that may prolong QT interval, or in those with symptoms suggesting arrhythmias.

Q5: What does a QTc of 426 ms indicate?
A: A QTc of 426 ms is generally considered within the normal range for most populations.