atrial escape rhythm

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Escape Rhythms

  • occurs when sinus node fails to produce an impulse, another focus in the heart takes over the duty and the ensueing rhyhtm is called escape rhythm

  • many different foci in the heart can produce regular impulses to depolarize the ventricles and to sustain a stable cardiac rhythm
    • focus with the highest frequency will be the dominant focus

  • in a normal heart, sinus node is the dominant pacemaker and sinus rhythm is the dominant rhythm since sinus node produces impulses with the highest frequency

  • the disease process resulting in the appearance of escape rhythm is more important than the escape rhythm itself

Different types of escape rhythms:

  • atrial escape rhythm:
    • every P wave is followed by a QRS complex but the shape of the P wave is different than that of the sinus beat
    • QRS complex is narrow and the heart rate is generally above 60/minute

  • atrioventricular (AV) nodal rhythm:
    • no P wave is expected to preceed the QRS complex.
    • QRS complexes are narrow
    • heart rate is between 40-60/minute

  • ventricular escape rhythm (idioventricular rhythm):
    • since QRS complexes originate from the ventricles, they are wide and there are no P waves preceed them. Heart rate is 25-40/minute.

For more information and an example ECG then click here

Last reviewed 01/2018