Overview
Definition
Complete failure of the AV node to conduct electrical impulses from the atria to the ventricles. The atria and ventricles beat independently of each other.
Epidemiology
A dangerous, symptomatic bradyarrhythmia requiring immediate attention.
Etiology & Risk Factors
- Degeneration of the conduction system
- Lyme disease
- Acute Anterior MI (implies extensive necrosis)
- Cardiac surgery
Clinical Symptoms
- Severe fatigue
- Syncope
- Heart failure
- Cardiovascular collapse
Clinical Approach
Diagnosis
- ECG: Complete AV dissociation. P waves are marching out at their own regular rate, and QRS complexes are marching out at a slower, completely independent escape rate (typically 30-40 bpm)
Management
- Immediate: Transcutaneous pacing, IV Atropine (though often ineffective in complete block), Dopamine or Epinephrine infusion
- Definitive: Permanent Pacemaker (PPM) placement
Complications
- Asystole
- Sudden Cardiac Death
- Severe heart failure