Back to Basics: Complete Heart Block

3rd Degree AV Block/Complete Heart Block

  • No association between P waves and QRS
  • If AV block in AV node - junctional escape pacemaker, ventricular rate 40-60 bpm

Associated with inferior acute MI, medications (BB, digoxin, CCB), hyperkalemia, myocarditis, rheumatic fever, SLE, Lyme disease

  • If AV block infranodal - ventricular escape rhythm at rate <40bpm 

Associated with anterior acute MI, infiltrative (amyloid, sarcoid), calcified valves, hereditary neuromuscular disease, iatrogenic (valve surgery)

  • Atrial rate>ventricular rate
  • Cardiac monitoring and plan for admission
  • May respond to atropine
  • Transcutaneous cardiac pacing
  • Transvenous cardiac pacing
  • Patient likley needs a Permanent pacemaker!


Brady WJ, Laughrey TS, Ghaemmaghami CA. “Cardiac Rhythm Disturbances." Tintinalli’s Emergency Medicine: A Comprehensive Study Guide, 8Eds. Judith E. Tintinalli, et al. New York, NY: McGraw-Hill, 2016, pg 121-3.

Goldberger AL, et al. “Atrioventricular (AV) Conduction Abnormalities, Part I: Delays, Blocs, and Dissociation Syndromes.” Goldberger’s Clinical Electrocardiography: a simplified approach, 9Eds. Philadelphia, PA: Elsevier, 2018, pg 172-182