Calculator

Corrected QT (Bazett)

New

QT ÷ √(RR in seconds). Over-corrects at fast heart rates.

ms
/min

QTc

447 ms

Normal

Normal
Prolonged
> 500 ms: high torsades risk

Formula

qt / sqrt(60 / hr)

References

  1. Bazett HC. An analysis of the time-relations of electrocardiograms. Heart 1920;7:353-70.

Used in

Peri-arrest rhythms: unstable tachycardia and bradycardiaVentricular tachycardia, wide-complex tachycardia and electrical stormInitial approach and toxidromesCardiotoxic overdoses: TCA, beta-blockers, CCB, digoxinQT prolongation, torsades and key ICU drug interactionsECG interpretation in the ICU

Calculators support, not replace, clinical judgement. Check inputs and units, and confirm doses with your unit protocol.