Second-Degree Atrioventricular Block Medication

Updated: Jun 28, 2022
  • Author: Ali A Sovari, MD, FACP, FACC; Chief Editor: Jeffrey N Rottman, MD  more...
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Medication Summary

Atropine can be used for immediate treatment of symptomatic second-degree atrioventricular (AV) block in the atrioventricular node (AVN). For block in the His-Purkinje system, atropine does not improve conduction and can actually precipitate third-degree AV block by increasing the sinus rate and AVN conduction.


Anticholinergic agents

Class Summary

Anticholinergic agents improve AV nodal conduction in second-degree block at the level of the AVN. Drug therapy in second-degree heart block is aimed at vagolysis; atropine is the only currently recommended agent.

Atropine IV/IM (AtroPen)

Atropine is used to increase heart rate through vagolytic effects, causing an increase in cardiac output. It enhances sinus node automaticity; in addition, it blocks the effects of acetylcholine at the AVN, thereby decreasing the refractory time and speeding conduction through the AVN. Insufficient doses of atropine can cause paradoxical effects, further slowing the heart rate.