Corrected QT Interval (QTc)

Corrects the QT interval for heart rate extremes.

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

Posted in: Cardiac • Cardiology









The NNT : Quick Summaries of Evidence-Based Medicine