Basic ECG Interpretation

Basic ECG Interpretation




Sinus rhythm
a normal heart beat, both with respect to the heart rate and rhythm.  Heart rate will fall between 60 and 100 beats per minute.     clickhere_blue25


Normal Sinus Rhythm

  • Regular rhythm at a rate of 60-100 bpm (or age-appropriate rate in children).
  • Each QRS complex is preceded by a normal P wave.
  • Normal P wave axis: P waves should be upright in leads I and II, inverted in aVR.
  • The PR interval remains constant.
  • QRS complexes are < 100 ms wide (unless a co-existent interventricular conduction delay is present).


the first short upward movement of ECG tracing, indicating the atria contracting, pumping blood into the ventricles.     clickhere_green25


T wave
a modest upwards waveform, representing ventricular repolarization.     clickhere_orange25


QRS Complex
representing ventricular depolarization and contraction, normally beginning with a downward deflection, Q; a larger upwards deflection, a peak (R); and then a downwards S wave.     clickhere_red25


PR interval
indicating the transit time for the electrical signal to travel from the sinus node to the ventricles.     clickhere_blue25


Sinus Bradycardia
A sinus rhythm with a resting heart rate of 60 beats per minute or less.  The action potential responsible for this rhythm arises from the sinus node and causes a P wave on the surface ECG that is normal in terms of both amplitude and vector.  These P waves are typically followed by a normal QRS complex and T wave.     clickhere_green25



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