1. What is Bazett's Formula?

Bazett's formula is a method for correcting the QT interval for heart rate, providing the QTc (corrected QT interval). It is commonly used in clinical practice to assess ventricular repolarization.

2. How Does the Calculator Work?

The calculator uses Bazett's 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 for heart rate, allowing for comparison across different heart rates.

3. Importance of QTc Calculation

Details: Accurate QTc calculation is crucial 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: Why use Bazett's formula?
A: Bazett's formula is widely used and accepted in clinical practice for heart rate correction of the QT interval.

Q2: What are normal QTc values?
A: Normal QTc is generally ≤440 ms for men and ≤460 ms for women. Prolonged QTc increases risk of arrhythmias.

Q3: When should QT be measured?
A: QT interval should be measured from the beginning of the QRS complex to the end of the T wave, preferably in lead II or V5.

Q4: Are there limitations to Bazett's formula?
A: Bazett's formula may overcorrect at high heart rates and undercorrect at low heart rates. Alternative formulas (e.g., Fridericia) may be used in certain cases.

Q5: Should this be used for drug safety assessment?
A: QTc assessment is critical in drug development and safety monitoring, especially for drugs known to affect cardiac repolarization.