What is the management of symptomatic bradycardia (slow heart rate)?

Management of Symptomatic Bradycardia

The management of symptomatic bradycardia requires immediate assessment of hemodynamic stability, followed by atropine administration as first-line therapy, with escalation to temporary pacing if needed, and addressing any reversible causes. 1

Initial Assessment and Stabilization

• Determine hemodynamic stability: Assess for symptoms of hemodynamic compromise:

  • Ischemic chest pain
  • Dyspnea
  • Syncope or altered mental status
  • Hypotension (systolic BP <90 mmHg)

• Identify and treat reversible causes 1:

  • Medications (beta-blockers, calcium channel blockers, digoxin, antiarrhythmics)
  • Electrolyte abnormalities (particularly hyperkalemia)
  • Hypothyroidism
  • Increased vagal tone
  • Hypoxemia
  • Acute myocardial ischemia/infarction
  • Sleep apnea

Pharmacological Management

First-Line Treatment

• Atropine 0.5-1 mg IV (may repeat every 3-5 minutes to maximum dose of 3 mg) 1, 2
  • Reasonable for symptomatic sinus node dysfunction with hemodynamic compromise
  • Monitor response after each dose
  • Caution: Ineffective in heart transplant patients due to denervation 1, 2

Second-Line Treatments (if atropine ineffective)

• Dopamine: 5-20 mcg/kg/min IV, starting at 5 mcg/kg/min and increasing by 5 mcg/kg/min every 2 minutes 1
• Isoproterenol: 20-60 mcg IV bolus followed by 10-20 mcg doses or infusion of 1-20 mcg/min 1
• Epinephrine: 2-10 mcg/min IV or 0.1-0.5 mcg/kg/min IV titrated to desired effect 1

Special Situations

• Heart transplant patients: Use aminophylline (250 mg IV bolus) instead of atropine 1, 2
• Beta-blocker overdose: Glucagon 3-10 mg IV with infusion of 3-5 mg/h 1, 2
• Calcium channel blocker overdose: 10% calcium chloride 1-2 g IV every 10-20 minutes 1
• Second or third-degree AV block with acute inferior MI: Aminophylline 250 mg IV bolus 1

Temporary Pacing

Transcutaneous Pacing

• Indications: Critically ill patients with hemodynamic instability due to bradycardia unresponsive to atropine 1, 3
• Implementation: Apply pads anteriorly and posteriorly, start at 80 bpm, gradually increase output until capture achieved
• Considerations: May cause discomfort; consider analgesia/sedation in conscious patients

Temporary Transvenous Pacing

• Indications: Hemodynamically unstable patients with persistent symptomatic bradycardia despite medical therapy 1
• Considerations: Associated with complications (14-40% in older studies) 1
• Best used when: Prolonged temporary pacing needed and permanent pacemaker implantation is not immediately available

Permanent Pacing Considerations

Permanent pacing should be considered for:

• Symptomatic bradycardia due to necessary medications that cannot be discontinued 2
• Symptomatic bradycardia with no reversible cause 2

Important: Permanent pacing should NOT be performed in 1:

• Asymptomatic individuals with sinus bradycardia
• Sleep-related sinus bradycardia or transient sinus pauses during sleep
• Patients whose symptoms occur in absence of bradycardia

Clinical Pearls and Pitfalls

• Efficacy of atropine: Approximately 50% of patients with symptomatic bradycardia respond to atropine therapy 4
• Bradycardia with hyperkalemia: Requires specific treatment of the electrolyte abnormality in addition to standard bradycardia management 5
• Transcutaneous pacing effectiveness: Most beneficial in patients who still have a palpable pulse when first evaluated 3
• Medication-induced bradycardia: Consider dose reduction or medication discontinuation before proceeding to invasive interventions 2

By following this structured approach to symptomatic bradycardia management, clinicians can effectively stabilize patients while addressing underlying causes, ultimately improving morbidity, mortality, and quality of life outcomes.