What is the American Heart Association (AHA) recommended treatment for symptomatic bradycardia?

AHA Management of Symptomatic Bradycardia

For symptomatic bradycardia, the American Heart Association recommends atropine as first-line treatment, followed by beta-adrenergic agonists or transcutaneous pacing if atropine is ineffective, while preparing for emergent transvenous temporary pacing if required. 1

Initial Assessment and Criteria for Treatment

• Symptomatic bradycardia requiring treatment is defined by the presence of signs and symptoms of instability, including:

  • Acutely altered mental status
  • Ischemic chest discomfort
  • Acute heart failure
  • Hypotension
  • Other signs of shock 1

• Asymptomatic bradycardia generally does not require immediate intervention 2

First-Line Treatment

• Atropine:

  • Recommended dose: 0.5-1 mg IV every 3-5 minutes to a maximum total dose of 3 mg 1
  • Class IIa recommendation with Level of Evidence B 1
  • Caution: Doses <0.5 mg may paradoxically worsen bradycardia due to central vagal stimulation 1, 3
  • Atropine is most effective for sinus bradycardia and AV nodal blocks 1, 3

• Special considerations with atropine:

  • Avoid in heart transplant patients (may cause paradoxical slowing) 1, 4
  • Use with caution in acute coronary ischemia or MI (may worsen ischemia) 1, 5
  • Less effective in type II second-degree or third-degree AV block with wide QRS complexes (infranodal blocks) 1, 6

Second-Line Treatments (if bradycardia is unresponsive to atropine)

• Beta-adrenergic agonists (Class IIa, LOE B) 1:

  • Dopamine: 5-20 mcg/kg/min IV, starting at 5 mcg/kg/min and increasing by 5 mcg/kg/min every 2 minutes 1
  • Epinephrine: 2-10 mcg/min IV or 0.1-0.5 mcg/kg/min IV titrated to desired effect 1
  • Isoproterenol: 20-60 mcg IV bolus followed by 1-20 mcg/min infusion (use with caution if coronary ischemia suspected) 1

• Transcutaneous pacing (TCP) (Class IIa, LOE B) 1:

  • Reasonable to initiate in unstable patients who do not respond to atropine 1
  • Should not be delayed while waiting for medication effect in patients with poor perfusion 1, 4
  • May be painful in conscious patients; consider sedation as appropriate 1

Third-Line Treatment

• Transvenous temporary pacing (Class IIa, LOE C) 1:
  • Indicated if the patient does not respond to drugs or TCP 1
  • For patients requiring prolonged temporary pacing, an externalized permanent active fixation lead is reasonable over a standard passive fixation temporary pacing lead 1

Special Clinical Scenarios

• Inferior MI with AV block:

  • Consider aminophylline (250 mg IV bolus) for second or third-degree AV block 1, 7

• Drug toxicity (beta-blockers or calcium channel blockers):

  • Calcium (calcium chloride 1-2 g IV or calcium gluconate 3-6 g IV) 1
  • Glucagon for beta-blocker or calcium channel blocker overdose 1

• Reversible causes:

  • Evaluate and treat potentially reversible causes before determining need for permanent pacing 1
  • Examples include drug toxicity, electrolyte abnormalities, and Lyme carditis 1

Long-Term Management

• Permanent pacing is indicated for persistent symptomatic bradycardia unresponsive to medical management 2, 8

• For infrequent symptoms (>30 days between episodes), consider long-term monitoring with an implantable cardiac monitor if initial evaluation is nondiagnostic 1