Normal ECG

The normal ECG has the following characteristics

  • Regular rhythm (<10% variation at RR intervals)

  • Heart rate of 60-100 bpm

  • P waves originating in the sinus node

    • Upright in I, II, aVF, and V2-V6 (best seen in II)

    • Inverted in aVR

    • Variable in III, and aVL

  • PR interval between 120-200 msec

  • QRS duration of 60-110 msec

  • QRS Axis of -30° to 90°

  • No pathologic Q waves

  • Isoelectric ST segments

  • Normal T Waves

    • Height <2/3 the size of the preceding R Wave

    • In the same direction of the predominant QRS deflection

  • Corrected QT interval:

    • 390-450 msec (men)

    • 390-460 msec (women)

Trevaylor Road

Falmouth

Cornwall  TR11 2LH

01326 210 090

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