1. What Is Bazett's Formula?

Bazett's formula is a widely used method to correct the QT interval for heart rate, providing the QTc (corrected QT interval). It helps in assessing the duration of ventricular repolarization, which is crucial for identifying potential cardiac risks.

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 = 60 / HR (s)
• \( HR \) — Heart rate (bpm)

Explanation: The formula adjusts the QT interval based on the heart rate to provide a standardized measure that can be compared across different heart rates.

3. Importance Of QTc Calculation

Details: Accurate QTc calculation is essential for diagnosing long QT syndrome, assessing drug-induced QT prolongation, and evaluating overall cardiac electrical stability.

4. Using The Calculator

Tips: Enter QT interval in milliseconds and heart rate in beats per minute. Both values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: Why correct QT interval for heart rate?
A: The QT interval naturally shortens with increasing heart rate. Correction allows comparison of QT values at different heart rates.

Q2: What are normal QTc values?
A: Normal QTc is typically <440 ms for men and <460 ms for women. Values above these may indicate prolonged QT.

Q3: Are there limitations to Bazett's formula?
A: Yes, it tends to overcorrect at high heart rates and undercorrect at low heart rates. Other formulas (Fridericia, Hodges) may be used in specific situations.

Q4: When should QTc be measured?
A: QTc should be measured in standard ECG leads, preferably lead II or V5, and averaged over multiple beats for accuracy.

Q5: What clinical conditions affect QTc?
A: Various conditions including electrolyte imbalances, medications, and congenital syndromes can prolong QTc and increase arrhythmia risk.