Doctaverse
Cardiology

Corrected QT Interval (QTc)

Heart-rate-corrected QT interval by Bazett and Fridericia, from the measured QT and heart rate.

Written for clinicians. If you're a parent or patient, don't act on these numbers — talk to your child's doctor.

Scope: Bazett is unreliable below HR 60 and above HR 100. Measure QT in lead II or V5 across several beats.

Inputs

FieldUnitNotes
QT interval ms Measured QT in milliseconds
Heart rate bpm 20–300

FAQ

What is the Corrected QT Interval (QTc)?

Heart-rate-corrected QT interval by Bazett and Fridericia, from the measured QT and heart rate.

What inputs does the Corrected QT Interval (QTc) need?

QT interval (ms), Heart rate (bpm).

Are there any limitations?

Bazett is unreliable below HR 60 and above HR 100. Measure QT in lead II or V5 across several beats.

Related guides

Pediatric QTc: Bazett vs Fridericia, and When Bazett Misleads

How to correct the QT interval in children — Bazett vs Fridericia, the >460 ms paediatric threshold, false positives at high heart rates, and a worked example.

Related Cardiology calculators

Pediatric Blood Pressure (AAP 2017)

Classifies a child's blood pressure against AAP 2017 norms (age/sex/height percentile for <13 y; absolute thresholds ≥13 y).

Mean Arterial Pressure (MAP)

Estimates mean arterial pressure from systolic and diastolic blood pressure.

Pediatric Echo Z-Score (Pettersen)

Body-surface-area-normalized z-score for cardiac structures from the Pettersen (Detroit) regression model.

Left Ventricular Fractional Shortening (FS)

Echocardiographic index of left-ventricular systolic function from M-mode dimensions.
Want this at the bedside, offline? Get the Doctaverse app — every calculator, diagnostic and the drug formulary in your pocket.