Units: US SI

Corrected QT Interval (QTc)

Heart Rate BPM
QT Interval msec
Corrected QT msec

Corrected QT (QTC) = Bazett's Formula = QT Interval / √ (RR interval)
RR Interval = 60/HR

Normal QTc ≤ 440 msec. A longer QTc puts the patient at increased risk for torsade de pointes.

Some causes of prolonged QT:

  • CAD
  • Cardiomyopathy
  • Severe Bradycardia, High-Grade AV Block
  • Anti-Arrhythmics
  • Psychotropic Drugs
  • Other Drugs
  • HypoCa, other lyte abnormalities
  • Autonomic dysfunction
  • Hypothyroid
  • Hypothermia
  • Congenital Long QT Syndrome

Posted in: Cardiac • Cardiology

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