Bradycardias, AV Block, and AV Dissociation

Sinus bradycardia (SB) (NEJM 2000;342:703)

  • Etiologies: meds (incl βB, CCB, amio, Li, dig), ↑ vagal tone (incl. athletes, sleep, IMI), metabolic (hypoxia, sepsis, myxedema, hypothermia, ↓ glc), OSA, ↑ ICP
  • Treatment: if no sx, none; atropine, β1 agonists (short-term) or pacing if symptomatic
  • Most common cause of sinus pause is blocked premature atrial beat

Sick sinus syndrome (SSS)

  • Features may include: periods of unprovoked SB, SA arrest, paroxysms of SB and atrial
    • tachyarrhythmias (“tachy-brady” syndrome), chronotropic incompetence w/ ETT
  • Treatment: meds alone usually q. control tachy → unacceptable brady); usually need