What are normal values for waves and intervals on electrocardiography (ECG)?

Updated: May 18, 2020
  • Author: Lawrence Rosenthal, MD, PhD, FACC, FHRS; Chief Editor: Buck Christensen  more...
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Normal ECG values for waves and intervals are as follows:

  • RR interval: 0.6-1.2 seconds
  • P wave: 80 milliseconds
  • PR interval: 120-200 milliseconds
  • PR segment: 50-120 milliseconds
  • QRS complex: 80-100 milliseconds
  • ST segment: 80-120 milliseconds
  • T wave: 160 milliseconds
  • QT interval: 420 milliseconds or less if heart rate is 60 beats per minute (bpm)

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