What is the treatment for complete heart block?

Treatment of Complete Heart Block

Permanent pacemaker implantation is the definitive treatment for complete heart block, as it significantly improves survival and prevents symptoms related to bradycardia. 1

Immediate Management

The approach to treating complete heart block depends on the patient's hemodynamic stability:

For Hemodynamically Unstable Patients:

1. Establish airway, breathing, and circulation
2. Administer atropine:
   • Dose: 0.5 mg IV, repeated every 3-5 minutes as needed
   • Maximum total dose: 3 mg
   • Note: Atropine is only effective for AV nodal blocks (not infranodal blocks) 2, 3
3. Transcutaneous pacing if no response to atropine
4. Beta-adrenergic agonists if needed:
   • Dopamine 2-10 μg/kg/min or
   • Epinephrine 2-10 μg/min 2

For Hemodynamically Stable Patients:

1. Identify and discontinue medications that may worsen AV conduction:
   • Beta-blockers
   • Non-dihydropyridine calcium channel blockers
   • Digitalis 2
2. Correct electrolyte abnormalities if present
3. Arrange for permanent pacemaker implantation

Indications for Permanent Pacemaker

The European Society of Cardiology and American College of Cardiology/American Heart Association guidelines recommend permanent pacemaker implantation for:

• All patients with third-degree (complete) AV block 1, 2
• Patients with symptomatic second-degree AV block
• Asymptomatic patients with Mobitz type II second-degree AV block 1

Special Considerations Based on Etiology

Complete Heart Block in Acute Myocardial Infarction:

• Inferior MI: AV block is usually at the level of the AV node
  • Often transient and may resolve within 14-16 days
  • Atropine may be effective 1
• Anterior MI: AV block is usually infra-nodal
  • Associated with extensive myocardial damage
  • Higher mortality risk
  • Permanent pacing often required 1

Congenital Complete Heart Block:

• Permanent pacing is indicated, especially with:
  • Heart rate <50 beats/min
  • Prolonged QT interval
  • Structural heart disease 1

Post-Procedural Complete Heart Block:

• After alcohol septal ablation or surgical myectomy:
  • If block persists >24 hours, permanent pacing is typically required 1
• After transcatheter aortic valve replacement (TAVR):
  • Permanent pacing required in approximately 15% of patients within 30 days 1

Prognosis

Untreated complete heart block has a poor prognosis. Historical data shows that patients with untreated complete heart block, especially those with Adams-Stokes attacks, have significantly lower survival rates compared to those who receive pacemakers 4.

Important Caveats

• Atropine may be ineffective or harmful in infranodal blocks (Mobitz Type II and infranodal third-degree blocks) 2, 3
• Temporary pacing should be considered as a bridge to permanent pacing in unstable patients
• Electrophysiologic studies may be helpful in determining the site of block when it cannot be established by ECG 1
• Regular follow-up is essential for patients with conditions that may progress to complete heart block (e.g., bifascicular block) 1

Complete heart block requires prompt recognition and appropriate management to prevent adverse outcomes including sudden cardiac death. The definitive treatment is permanent pacemaker implantation, which significantly improves survival and quality of life.