Medical calculators

QTc

Corrected QT Interval

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Anatium is a study resource, not medical advice. Nothing here is a diagnosis, a prescription or a substitute for a clinician who has seen the patient. Check every number against a current local protocol before it touches anyone, and never act on a result you cannot reproduce yourself.

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How it is calculated

Bazett formula: QT / √RR. Prolonged at 450 ms or more in men and 460 ms or more in women; short at 390 or below (AHA/ACCF/HRS 2009). Over 500 ms, or a rise of 60 ms from baseline on a drug, needs prompt action. Short QT syndrome (ESC 2022) needs 360 or below with symptoms, family history or a mutation, or 320 or below. Bazett over-corrects at fast heart rates.

About

The QT interval corrected for heart rate, screening for the prolongation that predisposes to torsades de pointes. Many common drugs prolong it.

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