Escape rhythms

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