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Atrioventricular Conduction: Physiology and Autonomic Influences

Eric N Prystowsky1, Jasen L Gilge2

  • 1Cardiac Arrhythmia Service, St. Vincent Hospital, 8333 Naab Road, Indianapolis, IN 46260, USA; Duke University Medical Center, Durham, NC, USA.

Cardiology Clinics
|June 15, 2023
PubMed

Insights

Sudden heart block often indicates increased vagal tone affecting the atrioventricular node. However, heart block with activity suggests the His-Purkinje system is involved, influenced by autonomic tone changes.

Area of Science:

  • Cardiology
  • Electrophysiology
  • Autonomic Nervous System

Background:

  • Atrioventricular (AV) nodal conduction exhibits decremental properties and is sensitive to autonomic tone.
  • His-Purkinje system (HPS) conduction relies on fast-channel tissue, making it less susceptible to autonomic influence.

Purpose of the Study:

  • To differentiate the location of heart block based on autonomic tone alterations.
  • To understand the role of autonomic perturbations in AV nodal and His-Purkinje system conduction.

Main Methods:

  • Analysis of electrophysiological principles governing AV nodal and HPS conduction.
  • Correlation of heart block patterns with changes in sinus rate and autonomic tone.

Main Results:

  • Sudden heart block during stable sinus rate, preceded by slowing, typically implicates the AV node due to increased vagal tone.
  • Heart block accompanied by activity suggests a block within the His-Purkinje system.
  • Enhanced sympathetic and reduced vagal tone can promote AV and atrioventricular node reentry.

Conclusions:

  • Autonomic tone significantly impacts AV nodal conduction, often causing block.
  • Heart block location can be inferred from its relationship with sinus rate and autonomic state.
  • Understanding these principles aids in diagnosing the origin of heart block.

Keywords:
AV nodeAV node reentryAutonomic nervous systemConductionHis-Purkinje systemParasympatheticSympatheticWPW reentry

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