ACLS: Bradycardia

Background

  • Only intervene if pt is symptomatic (hypotension, AMS, chest pain, pulm edema)

Categories

  1. Sinus node dysfunction
    1. Sinus bradycardia
    2. Sinus arrest
    3. Tachy-brady syndrome (sick sinus)
    4. Chronotropic incompetence
  2. AV node dysfunction
    1. 1st degree AV block
    2. 2nd degree AV block Mobitz I/Wenckebach
    3. 2nd degree AV block Mobitz II
    4. 3rd degree AV block (complete heart block)

Differential

  1. Ischemia/Infarction
    1. Inferior MI (involving RCA)
  2. Neurocardiogenic/reflex-mediated
    1. Increased ICP
    2. Vasovagal reflex
    3. Hypersensitive carotid sinus syndrome
    4. Intra-abdominal hemorrhage (i.e. ruptured ectopic)
  3. Metabolic/endocrine/environmental
    1. Hyperkalemia
    2. Hypothermia (Osborn waves on ECG)
    3. Hypothyrodism
  4. Toxicologic
    1. Digoxin toxicity
  5. Infectious/Postinfectious
    1. Chagas dz
    2. Lyme dz
    3. Syphilis

Treatment

  1. Atropine
    1. Can be used as temporizing measure (while awaiting pacing and/or chronotropes)
    2. Use cautiously in pts w/ ongoing ischemia (tachycardia may worsen ischemia)
    3. 0.5mg q3-5min (max 3 mg or 6 doses)
      1. may not work in 2nd/3rd deg HB, heart transplantTranscutaneous pacing
  2. Chronotropes
    1. Dopamine 2-10mcg/kg/min
    2. Epinephrine 2-10mcg/min
  3. Transcutaneous pacing
    1. Set: HR 80, pacing threshold usually btwn 40-80 mA
      1. Look for clear QRS complex and T-wave following pacer spike
      2. Check pulse to confirm mechanical capture
      3. Final current set 5-10 mA above threshold level for pt
    2. Pad placement:
      1. Pad on apex of heart and other on R upper chest
      2. Pad on lead V3 position and btwn L scapula and T-spine
  4. Transvenous pacing
    1. Required if transcutaneous pacing + chronotropes is ineffective
    2. Set: HR 80, max current output (usually 20 mA)
      1. Final current set to twice the threshold level for pt

See Also