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's essential for assessing cardiac repolarization and detecting potential arrhythmia 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 calculated as 60 / HR (seconds)
• \( HR \) — Heart rate (beats per minute)

Normal Values: QTc <440 ms for men, QTc <460 ms for women

3. Importance of QTc Calculation

Details: Corrected QT interval assessment is crucial for detecting long QT syndrome, evaluating drug-induced QT prolongation, and assessing cardiac safety in various clinical settings.

4. Using the Calculator

Tips: Enter QT interval in milliseconds, heart rate in beats per minute, and select gender. All 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 across different heart rates.

Q2: What are the limitations of Bazett's formula?
A: It may overcorrect at high heart rates and undercorrect at low heart rates. Other formulas like Fridericia may be used in specific cases.

Q3: When is QTc considered prolonged?
A: Generally, QTc >450 ms in men and >470 ms in women is considered prolonged and may indicate increased arrhythmia risk.

Q4: How should QT interval be measured?
A: Measure from the beginning of the QRS complex to the end of the T wave, preferably in lead II or V5, averaging 3-5 beats.

Q5: What clinical conditions affect QTc?
A: Electrolyte imbalances, medications, congenital long QT syndrome, myocardial ischemia, and various cardiac conditions can affect QTc.