I. Clinical features

  1. An "automatic" (ectopic) rhythm
  2. Atria & ventricles are depolarized simultaneously
  3. Often due to "AV Nodal Reentry" in which a continuous circuit conducts impulses in a circular pathway within the AV node (and sometimes lower atria)
  4. QRS is narrow; (if no BBB), inverted p waves, ventr. rate us. 70-150
  5. Usually well-tolerated but loss of atrial kick can worsen CHF; usually see constant cannon waves in JV pulses

II. Etiology: ischemia, myocarditis; dig

III. Treatment

  1. Treat underlying conditions
  2. IA antiarrhythmics or beta-blockers
  3. Atrial pacing may suppress ectopic focus in severe cases
  4. Not responsive to vagal maneuvers