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Table 44.1

Classification of Bradycardia and Atrioventricular (AV) Block

Bradycardia (sinus node disease and atrioventricular block)
  • Sinus bradycardia (see Table 44.3 for causes)
  • Second-degree sino-atrial exit block
  • Junctional escape secondary to profound sinus bradycardia or complete sino-atrial exit block or sinus arrest (Figure 44.2)
  • Atrial fibrillation with slow ventricular rate (distinguished from atrial fibrillation with complete AV block by irregular RR interval)
  • Atrial flutter/atrial tachycardia with high grade AV block
  • Complete AV block with junctional or ventricular escape rhythm (Figure 44.6)
Atrioventricular block (see Table 44.4 for causes)
  • First degree AV block (constant PR interval >200 ms)
  • Second degree AV block, Mobitz type 1 (Wenckebach) (Figure 44.3)
  • 2:1 second degree AV block (Figure 44.3)
  • Second degree AV block, Mobitz type 2 (Figure 44.4)
  • High grade AV block (e.g. 4;1 or 5:1 AV block)
  • Third degree/complete AV block with junctional or ventricular escape rhythm (Figure 44.5)