ACLS: bradycardia

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

Background

• Heart rate < 60
• Intervention indicated if patient is symptomatic or experiencing symptoms of end organ damage (chest pain, altered mental status, shortness of breath, hypotension)

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 type I (Wenkebach)
  • 2nd degree AV block type 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

Algorithm for bradycardia with a pulse (Adapted from ACLS 2010)

• Atropine
  • Can be used as temporizing measure (while awaiting pacing and/or chronotropes)
  • Use cautiously in patients with ongoing ischemia (tachycardia may worsen ischemia)
  • Avoid and/or do not rely on in wide complex bradycardia, especially in setting of ischemia
  • 1 mg q3-5 min IV (max 3 mg)
    • 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 5-20 mcg/kg/min IV drip
  • Dobutamine 2-20 mcg/kg/min IV drip
  • Epinephrine 2-10 mcg/min (0.03-0.2 mcg/kg/min) IV drip
  • Isoproterenol 2-10 mcg/min IV drip
• Transcutaneous Pacing
• Transvenous Pacing

Antidotes for toxicologic causes

• Beta-Blocker Toxicity
  • Glucagon 5 mg q10 min (up to 3 doses) IV
  • Insulin 1 U/kg bolus IV
  • Intralipid (ILE)
• Calcium Channel Blocker Toxicity
  • Calcium gluconate 3 g IV
  • Insulin 1 U/kg bolus IV
  • Intralipid (ILE)
• Digoxin Toxicity
  • Dig immune Fab 10-20 vials IV
• Opioid Toxicity
  • Naloxone 0.4 mg IV
• Organophosphate Toxicity
  • Atropine 2 mg, double q5-30 min until secretions controlled IV
  • Pralidoxime 1-2 g over 15-30 min IV

Disposition

• Admit to telemetry/ICU for:
  • Symptomatic bradycardia requiring pharmacologic or pacing intervention
  • High-degree AV block (second-degree type II, third-degree)
  • Bradycardia with hemodynamic instability
  • New-onset bradycardia of unclear etiology
• Cardiology consultation for all patients requiring temporary pacing
• Discharge with outpatient cardiology follow-up for:
  • Asymptomatic sinus bradycardia with rate >50 in young/athletic patients
  • Known stable bradycardia at baseline

See Also

• ACLS (Main)

External Links

• DDxOf: Simplified ACLS Algorithms
• EM Cases Treatment of Bradycardia and Bradydysrhythmias