What is the algorithm for managing symptomatic bradycardia?

Algorithm for Managing Symptomatic Bradycardia

For patients with symptomatic bradycardia, the initial treatment is atropine, followed by intravenous infusion of β-adrenergic agonists or transcutaneous pacing if bradycardia is unresponsive to atropine. 1

Initial Assessment

• Confirm bradycardia (heart rate <60 bpm)
• Assess for symptoms of instability:
  • Acutely altered mental status
  • Ischemic chest discomfort
  • Acute heart failure
  • Hypotension
  • Signs of shock

Step 1: First-Line Treatment

• Atropine 0.5-1 mg IV every 3-5 minutes (maximum total dose 3 mg) 1, 2
• Monitor response after each dose

Caution with Atropine

• May be ineffective in heart transplant patients 2
• May cause paradoxical worsening in patients with infranodal (His-Purkinje) blocks 3
• Consider location of block before administration when possible

Step 2: If Unresponsive to Atropine

• Initiate transcutaneous pacing (TCP) 1 OR
• Begin IV infusion of β-adrenergic agonists 1
  • Dopamine infusion (2-10 mcg/kg/min) 1, 2
  • Epinephrine infusion (2-10 mcg/min) 2

Step 3: If Still Unresponsive

• Transvenous temporary pacing is indicated 1
• Consider immediate pacing in patients with high-degree AV block when IV access is not available 1

Special Considerations

Reversible Causes

• Identify and treat reversible causes:
  • Medication effects (beta-blockers, calcium channel blockers, digoxin) 2
  • Electrolyte abnormalities 2
  • Increased vagal tone 2
  • Lyme carditis 1

Medication-Induced Bradycardia

• For beta-blocker overdose: high-dose glucagon 2
• For calcium channel blocker overdose: calcium administration plus epinephrine 2
• For chronic stable doses of necessary medications causing bradycardia: consider proceeding directly to permanent pacing 1

Alternative Pharmacologic Options

• In selected cases where permanent pacing is not feasible:
  • Trial of oral theophylline (400-600 mg/day or ~8 mg/kg/day) may be considered for chronic symptomatic bradycardia 1, 4
  • Aminophylline may be effective in cases resistant to atropine 5

Long-Term Management

• For persistent symptomatic bradycardia:
  • Evaluate for permanent pacemaker placement 1
  • For sinus node dysfunction: atrial-based pacing is recommended over single chamber ventricular pacing 1
  • For patients with tachy-brady syndrome: permanent pacing is reasonable 1

Monitoring During Treatment

• Continuous cardiac monitoring
• Regular vital sign assessment
• Evaluation for signs of hemodynamic instability 2
• Monitor for adverse effects of medications

This algorithm provides a structured approach to managing symptomatic bradycardia, starting with atropine as first-line therapy and progressing to more advanced interventions if needed, while addressing potential reversible causes and special considerations for specific patient populations.