Characteristics of a normal ECG

• Rhythm: sinus rhythm
• Rate: 60-100 bpm
• Conduction:
  • PQ interval 120-200ms
  • QRS width 60-100ms
  • QTc interval 390-450ms (use the QTc calculator for this)
• Heart axis: between -30 and +90 degrees
• P wave morphology:
  • The maximal height of the P wave is 2.5 mm in leads II and / or III
  • The p wave is positive in II and AVF, and bifasic in V1
  • The p wave duration is usually shorter than 0.12 seconds
• QRS morphology:
  • No pathological Q waves
  • No left or right ventricular hypertrophy
  • No microvoltations
  • Normal R wave propagation. (R waves increase in amplitude from V1-V5)
• ST morphology
  • No ST elevation or depression
  • T waves should be concordant with the QRS complex

• The ECG should not have changed from the previous ECG