What is the management of symptomatic bradycardia?

Management of Symptomatic Bradycardia

For symptomatic bradycardia, treatment should begin with atropine 0.5-1 mg IV (repeatable every 3-5 minutes to a maximum of 3 mg), followed by vasopressors if ineffective, and then temporary pacing for persistent cases. 1

Initial Assessment and Reversible Causes

Before initiating treatment, quickly assess for:

• Hemodynamic stability (blood pressure, perfusion)
• Symptoms (altered mental status, chest pain, dyspnea, syncope)
• Potential reversible causes:
  • Medications (beta-blockers, calcium channel blockers, digoxin)
  • Electrolyte abnormalities (hyperkalemia)
  • Hypothyroidism
  • Increased vagal tone
  • Acute myocardial infarction/ischemia

Treatment Algorithm for Symptomatic Bradycardia

Step 1: Pharmacological Management

• Atropine 0.5-1 mg IV (may repeat every 3-5 minutes to maximum 3 mg) 1
  • Use caution with doses <0.5 mg which may paradoxically worsen bradycardia
  • AVOID in infranodal AV block (may worsen block) 1, 2
  • AVOID in heart transplant patients without evidence of reinnervation 1

Step 2: If Atropine Ineffective

• Dopamine 5-20 mcg/kg/min IV (start at 5 mcg/kg/min, increase by 5 mcg/kg/min every 2 minutes) 1
• Epinephrine 2-10 mcg/min IV or 0.1-0.5 mcg/kg/min IV 1
• Isoproterenol 20-60 mcg IV bolus followed by 10-20 mcg doses, or infusion of 1-20 mcg/min 1

Step 3: For Persistent Symptomatic Bradycardia

• Transcutaneous pacing for temporary support 1
• Transvenous temporary pacing if bradycardia persists with hemodynamic instability 1

Special Situations

Bradycardia Due to Medication Overdose

• Beta-blocker or calcium channel blocker overdose:

  • Glucagon 3-10 mg IV with infusion of 3-5 mg/h 1
  • High-dose insulin therapy (1 unit/kg IV bolus followed by 0.5 units/kg/h infusion) 1

• Calcium channel blocker overdose:

  • 10% calcium chloride 1-2 g IV every 10-20 min or infusion of 0.2-0.4 mL/kg/h 1
  • 10% calcium gluconate 3-6 g IV every 10-20 min or infusion at 0.6-1.2 mL/kg/h 1

Post-Heart Transplant Bradycardia

• Aminophylline 6 mg/kg in 100-200 mL IV fluid over 20-30 min 1
• Theophylline 300 mg IV, followed by oral dose of 5-10 mg/kg/day 1, 3

Spinal Cord Injury-Related Bradycardia

• Aminophylline 6 mg/kg in 100-200 mL IV fluid over 20-30 min 1, 4
• Theophylline oral dose of 5-10 mg/kg/day 1

Indications for Permanent Pacing

Consider permanent pacemaker for:

• Persistent symptomatic bradycardia not responding to medical therapy
• High-grade or third-degree AV block
• Symptomatic Mobitz type II second-degree AV block 5

Clinical Pearls and Pitfalls

• Pitfall: Using atropine in infranodal AV block can worsen bradycardia and potentially cause asystole 2
• Pitfall: Doses of atropine less than 0.5 mg may paradoxically worsen bradycardia 1
• Pitfall: Excessive dopamine doses (>20 mcg/kg/min) may cause vasoconstriction and arrhythmias 1
• Pearl: In asymptomatic patients with bradycardia, observation without intervention is appropriate 1
• Pearl: Theophylline can be effective for chronic symptomatic bradycardia in elderly patients who cannot receive pacemakers 3
• Pearl: For patients with tachy-brady syndrome, treatment of the tachyarrhythmia component may improve sinus node function 1

Remember that symptomatic bradycardia requires prompt intervention to prevent progression to cardiac arrest, while asymptomatic bradycardia generally does not require acute treatment.