QTc Fridericia Calculator
The QTc Fridericia Calculator estimates the corrected QT interval based on the raw QT measurement and heart rate. This tool helps healthcare professionals accurately assess cardiac repolarization time for better patient care. Whether you are monitoring medication effects, evaluating electrolyte imbalances, or screening for arrhythmias, this calculator provides reliable results. It offers a standardized method to ensure consistency across different heart rates.
How Corrected QT Interval Is Calculated
The corrected QT interval (QTc) represents the heart's electrical recharge time adjusted for how fast the heart is beating. Since a fast heart rate naturally shortens the QT interval, a correction formula is necessary for accurate assessment. This tool uses Fridericia’s formula, which is often more accurate than other methods at higher heart rates.
QTc = QT / (RR interval)^(1/3)
Where:
- QTc = Corrected QT interval
- QT = Measured QT interval (ms)
- RR interval = 60,000 / Heart Rate
First, the tool converts the heart rate into the RR interval (time between beats). Then, it divides the measured QT interval by the cube root of the RR interval to find the QTc. This method ensures consistency and accuracy in clinical settings.
What Your Corrected QT Interval Means
Your result shows how long the heart takes to reset electrically between beats. A prolonged interval means the heart is vulnerable to dangerous irregular rhythms. **Normal results** are typically below 430 ms for males and 450 ms for females, indicating safe cardiac repolarization. **Borderline results** range from 430-450 ms for men and 450-470 ms for women. In this range, you should review the patient's electrolyte levels and current medications. **Prolonged results** exceed 450 ms in men or 470 ms in women and indicate a high risk of serious arrhythmias like torsades de pointes. Immediate clinical review is often required for these values.
Important
Always ensure the original QT measurement is accurate and exclude U waves unless they merge with the T wave.
This calculator is for informational purposes only and not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider for medical decisions.
Re-evaluate the QTc whenever the patient's heart rate or medication changes significantly.