ACLS: Bradycardia

This page is for bradycardia with a pulse; for bradycardia without a pulse see Adult Pulseless Arrest (i.e. PEA)

Background

• HR < 60
• Intervention only necessary if pt is symptomatic (hypotension, AMS, chest pain, pulm edema)

Categories

• Sinus node dysfunction
  • Sinus bradycardia
  • Sinus arrest
  • Tachy-Brady Syndrome (Sick Sinus)
  • Chronotropic incompetence
• AV node dysfunction
  • 1st degree AV block
  • 2nd degree AV block Mobitz I/Wenckebach
  • 2nd degree AV block Mobitz II
  • 3rd degree AV block (complete heart block)

Differential Diagnosis

Symptomatic bradycardia

• Cardiac
  • Inferior MI (involving RCA)
  • Sick sinus syndrome
• Neurocardiogenic/reflex-mediated
  • Increased ICP
  • Vasovagal reflex
  • Hypersensitive carotid sinus syndrome
  • Intra-abdominal hemorrhage (i.e. ruptured ectopic)
• Metabolic/endocrine/environmental
  • Hyperkalemia
  • Hypothermia (Osborn waves on ECG)
  • Hypothyroidism
    • Myxedema coma
  • Hypoglycemia (neonates)
• Toxicologic
  • B-blocker
  • Ca-channel blocker
  • Clonidine
  • Digoxin toxicity
  • Ethanol
  • Opioids
  • Organophosphates
  • Xylazine toxicity
• Infectious/Postinfectious
  • Chagas disease
  • Lyme disease
  • Syphilis
• Other
  • Brash syndrome

Management

• Atropine
  • Can be used as temporizing measure (while awaiting pacing and/or chronotropes)
  • Use cautiously in patients with ongoing ischemia (tachycardia may worsen ischemia)
  • 0.5mg q3-5min (max 3mg or 6 doses)
    • May not work in 2nd/3rd degree heart block, heart transplant
    • Priority is to use external cardiac pacemaking
    • Block is below AV node so atropine will accelerate sinus rate, leading to worsening of block and increased fatigue of AV nodal cells
• Chronotropes
  • Dopamine 2-10mcg/kg/min
  • Epinephrine 2-10mcg/min
• Transcutaneous Pacing
• Transvenous Pacing

Antidotes for toxicologic causes

• Beta-Blocker Toxicity
  • Glucagon 5mg IV Q10min (rpt up to 3 doses)
  • Insulin 1U/kg bolus
  • Intralipid (ILE)
• Calcium Channel Blocker Toxicity
  • Calcium gluconate 3g
  • Insulin 1U/kg bolus
  • Intralipid (ILE)
• Digoxin Toxicity
  • Dig immune Fab 10-20 vials
• Opioid Toxicity
  • Naloxone 0.4mg IV
• Organophosphate Toxicity
  • Atropine 2mg IV, double dose q5-30m until secretions controlled
  • Pralidoxime 1-2g IV over 15-30min

See Also

• ACLS (Main)