← Clinical Scores and Calculators
QTc Calculator
Correct the QT interval for heart rate. Monitor for drug-induced QT prolongation and torsades de pointes risk.
Indication
- Correct the QT interval for heart rate. Monitor for drug-induced QT prolongation and torsades de pointes risk.
Criteria
- id: qt; label: QT Interval (ms); type: number; placeholder: e.g. 420
- id: hr; label: Heart Rate (bpm); type: number; placeholder: e.g. 75
- id: sex; label: Sex; type: options; options: value: male; label: Male; value: female; label: Female
Clinical pearls
- QT prolongation is a class effect of many drugs — check crediblemeds.org for drug-drug interactions
- Correct hypokalemia and hypomagnesemia before and during QT-prolonging drug use
- Bazett overcorrects at high heart rates — use Fridericia when HR >100
- QTc >500 ms markedly increases the risk of torsades de pointes
Source and review
- Bazett HC. Heart 1920; Drew BJ et al. Circulation 2010. Last reviewed: 2025-01-01