Diagnostic criteria


  Sinus node cannot depolarize the atrium at the expected time. This results in a long isoelectric line between the last QRS complex before exit block and the first P wave coming after the exit block.

  The next sinus P wave comes at a multiple of the previous PP intervals. This feature differentiates sinoatrial exit block from sinus arrest.



Causes

  Excessive vagal stimulation

  Myocardial infarction

  Myocarditis

  Drugs: Digoxin, Procainamide, Quinidine, Propafenone



Reference

  Bratisl Lek Listy 2004;105:14-17.




ECG 1. Sinoatrial exit block.

Dr. Peter Kukla has donated this ECG to our website.

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ECG 2. Sinoatrial exit block.

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