Calculator · Cardiovascular

QTc (Bazett)

Heart-rate-corrected QT interval.

What it is for

Before/after QT-prolonging drugs (citalopram, escitalopram, antipsychotics, macrolides, methadone).

Use the working calculator

The working QTc (Bazett) calculator is on our calculators page. It is free and needs no account. Enter the values and it shows the result with the reading that goes with it.

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What you enter

The calculator asks for 3 items.

  • Measured QT interval (ms)
  • Heart rate (/min)
  • Female (higher normal threshold)

How the result is read

The result is shown as QTc in ms. Formula: QTc = QT / √(RR), RR = 60 / HR (seconds)

The calculator reports one of these readings, with the action that goes with it: Markedly prolonged; Prolonged; Borderline; Normal.

Sources

These are the sources the calculator cites. Check the current version before relying on a threshold.

Related

CHA₂DS₂-VAScStroke risk score in non-valvular AF.HAS-BLEDMajor bleeding risk on anticoagulation for AF.ORBITAlternative bleeding risk score for AF — may outperform HAS-BLED.QRISK3 (10-year CV risk)Predicts 10-year risk of MI / stroke. Proprietary algorithm. For education and practice only. For patient care, use the QRISK3 tool built into your clinical system (NICE NG238).ABCD₂ (TIA stroke risk)Risk of stroke after TIA within 7 days.All calculators60 clinical scores and tools

For qualified clinicians. A score supports a clinical decision and does not make it: check the inputs, read the cited source, and use the tools in your clinical system for patient care where one is provided.