🫀 Corrected QT (Multi-Formula Comparison)
UseEnter the measured QT and heart rate (or RR); the tool returns QTc by several methods. At extreme heart rates…
SourceVandenberk B, et al. Which QT Correction Formulae to Use for QT Monitoring?
This-shift next steps
After scoring: open the scene pack, peer scores, and the matching pathway. Local reference — no HIS write.
Paste the link in Slack, Teams, X, or LinkedIn — the preview image comes from this page’s Open Graph card.
Methodology · worked example, guidelines & full notes
Bazett systematically over-corrects at tachycardia and under-corrects at bradycardia; Fridericia and Framingham are more rate-stable and preferred outside HR 60–100. (original synthesis · not guideline verbatim)
When to use
Enter the measured QT and heart rate (or RR); the tool returns QTc by several methods. At extreme heart rates, prefer Fridericia/Framingham over Bazett, which over-corrects at high rates and under-corrects at low rates.
How it works
RR(s) = 60/HR. Bazett QTc = QT/√RR; Fridericia QTc = QT/RR^(1/3); Framingham QTc = QT + 154×(1−RR); Hodges QTc = QT + 1.75×(HR−60). Prolonged: > 450 ms (male) / > 470 ms (female); > 500 ms markedly raises torsades risk.
Key points
- Bazett systematically over-corrects at tachycardia and under-corrects at bradycardia; Fridericia and Framingham are more rate-stable and preferred outside HR 60–100. (original synthesis · not guideline verbatim)
- QTc > 500 ms, or a drug-induced increase ≥ 60 ms from baseline, substantially raises the risk of torsades de pointes.
- Correct hypokalemia/hypomagnesemia and review QT-prolonging drugs; in wide QRS or bundle branch block, raw QT measurement and correction both become unreliable.
References
Worked calculation
The values below come from this tool's own example placeholders and are computed server-side with the formula shown on this page, so the arithmetic can be checked quickly. It demonstrates how to substitute values only — it is not clinical advice and not a real case.
| QT interval | 400 ms |
|---|---|
| Heart rate | 75 bpm |
| Sex | Male |
→QTc (Fridericia)431ms
- Bazett：447 ms
- Fridericia：431 ms
- Framingham：431 ms
Verification & sources · governance
FAQ
Frequently asked questions
- What are the limits and cautions when using Corrected QT (Multi-Formula Comparison)?
- For licensed clinicians and clinical researchers. Interpret results with history, investigations and local protocols; not a diagnosis or prescription, and not a substitute for multidisciplinary decision-making or local guidelines.
- Does Corrected QT (Multi-Formula Comparison) upload patient data? Where is it calculated?
- Calculation runs locally in the browser; inputs and results are not uploaded. For licensed clinicians only; interpret with history, investigations and local protocols — not a diagnosis or prescription.
- How is Corrected QT (Multi-Formula Comparison) calculated in practice? Can you show a worked example?
- Inputs: QT interval 400 ms, Heart rate 75 bpm, Sex Male → Result: QTc (Fridericia) 431 ms（Bazett: 447 ms, Fridericia: 431 ms, Framingham: 431 ms）