What are the signs and symptoms of third-degree atrioventricular (AV) block?

Updated: Jul 05, 2018
  • Author: Akanksha Agrawal, MBBS; Chief Editor: Jeffrey N Rottman, MD  more...
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Third-degree atrioventricular (AV) block (complete heart block) has a wide range of clinical presentations. Occasionally, patients are asymptomatic or have only minimal symptoms related to hypoperfusion. In these situations, symptoms include the following:

  • Fatigue

  • Dizziness

  • Impaired exercise tolerance

  • Chest pain

Patients with narrow complex escape rhythms (eg, those whose escape rhythm occurs above the His bundle) are more likely to have minimal symptoms.

More commonly, however, patients are profoundly symptomatic, especially if a wide-complex escape rhythm is present, indicating that the origin of the pacemaker is below the His bundle. In such cases, symptoms can include the following:

  • Syncope

  • Confusion

  • Dyspnea

  • Severe chest pain

  • Sudden death

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