1. What Is The Bazett Formula?

The Bazett formula is a widely used method for correcting the QT interval for heart rate, providing the QTc (corrected QT interval). It helps in assessing the risk of arrhythmias by standardizing QT measurements across different heart rates.

2. How Does The Calculator Work?

The calculator uses the Bazett formula:

Where:

• \( QT \) — Measured QT interval from start of Q wave to end of T wave (ms)
• \( RR \) — RR interval = 60 / HR (s)
• \( HR \) — Heart rate (bpm)

Explanation: The formula adjusts the QT interval based on the square root of the RR interval to account for heart rate variations.

3. Importance Of QTc Calculation

Details: Accurate QTc calculation is essential for diagnosing long QT syndrome, assessing arrhythmia risk, and monitoring drug effects on cardiac repolarization.

4. Using The Calculator

Tips: Enter QT interval in milliseconds and heart rate in beats per minute. All values must be valid (QT > 0, HR > 0).

5. Frequently Asked Questions (FAQ)

Q1: What is a normal QTc value?
A: Normal QTc is typically < 440 ms for men and < 460 ms for women. Values above these may indicate prolonged QT.

Q2: Why is QTc important?
A: Prolonged QTc is associated with an increased risk of life-threatening arrhythmias like torsades de pointes.

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

Q4: When should QTc be measured?
A: QTc should be measured in patients on QT-prolonging drugs, with syncope, or with a family history of sudden cardiac death.

Q5: How is QTc interpreted?
A: QTc > 500 ms is considered high risk for arrhythmias, while values between 440-500 ms require monitoring and possible intervention.