What is the treatment for symptomatic premature atrial contractions (PACs)?

Treatment for Symptomatic Premature Atrial Contractions

Beta blockers are the first-line treatment for symptomatic premature atrial contractions (PACs), with non-dihydropyridine calcium channel blockers as alternatives when beta blockers are contraindicated.

Initial Evaluation and Management

When evaluating patients with symptomatic PACs, consider:

• Rule out reversible causes:

  • Electrolyte abnormalities
  • Hyperthyroidism
  • Stimulant use (caffeine, alcohol)
  • Medications that may trigger PACs

• Risk factor modification is essential:

  • Weight loss for overweight/obese patients (target 10% reduction) 1
  • Physical activity (tailored exercise program) 1, 2
  • Alcohol reduction (≤3 standard drinks per week) 1

Pharmacological Management

First-line Therapy

• Beta blockers (e.g., metoprolol 25-100 mg orally twice daily) 3, 4
  • Particularly useful in patients with coexisting hypertension, coronary artery disease, or heart failure
  • Caution in patients with bronchospastic lung disease

Alternative First-line Therapy

• Non-dihydropyridine calcium channel blockers (e.g., diltiazem 40-120 mg orally three times daily) 1, 3
  • Good option when beta blockers are contraindicated
  • Avoid in patients with heart failure with reduced ejection fraction
  • Recommended first-line for patients with COPD 1

Second-line Therapy

For patients who remain symptomatic despite first-line therapy:

• Flecainide (starting dose 50 mg every 12 hours, may increase in 50 mg increments every 4 days, maximum 300 mg/day) 1, 5

  • Contraindicated in structural heart disease
  • Requires careful monitoring
  • FDA-approved for PAF

• Propafenone (starting dose based on weight, typically 150 mg every 8 hours) 1, 6

  • Contraindicated in structural heart disease
  • Has shown efficacy in clinical trials for paroxysmal atrial arrhythmias 6

Invasive Management

For patients with highly symptomatic, drug-refractory PACs:

• Catheter ablation should be considered when:
  • PACs remain symptomatic despite adequate trials of medications
  • PACs are frequent (typically >5% burden)
  • PACs originate from a focal source that can be mapped 7

Catheter ablation has shown high success rates (>95%) with significant improvement in quality of life and reduction in PAC burden in patients with structurally normal hearts 7.

Clinical Considerations and Monitoring

Monitoring Response

• 24-hour Holter monitoring to assess PAC burden before and after treatment
• Follow-up ECG to document response to therapy
• Assess symptom improvement using standardized questionnaires

Special Considerations

• PACs are no longer considered benign - frequent PACs are associated with:

  • Increased risk of developing atrial fibrillation 4, 8
  • Impaired left atrial contractile function 9
  • Adverse left atrial remodeling 9
  • Potential increased stroke risk 8

• Patients with very frequent PACs (>5% burden) may benefit from more aggressive therapy even if minimally symptomatic, given the association with atrial cardiomyopathy 8, 9

Treatment Algorithm

1. Start with risk factor modification (weight loss, exercise, alcohol reduction)
2. If still symptomatic, initiate beta blocker (or calcium channel blocker if beta blockers contraindicated)
3. If inadequate response, consider adding or switching to flecainide or propafenone (in patients without structural heart disease)
4. For drug-refractory cases with significant symptoms, refer for electrophysiology evaluation and possible catheter ablation

Remember that even asymptomatic frequent PACs may warrant treatment consideration due to their association with atrial fibrillation and adverse atrial remodeling.