What is the preferred beta-blocker, metoprolol (Lopressor) or atenolol (Tenormin), for treating premature ventricular complexes (PVCs)?

Beta-Blocker Selection for Premature Ventricular Complexes (PVCs)

Atenolol is the preferred beta-blocker for treating symptomatic PVCs in patients with structurally normal hearts, as it has demonstrated superior efficacy in reducing both symptom frequency and PVC count in randomized controlled trials. 1

Evidence-Based Selection Process

First-Line Treatment Options

• Beta-blockers are recommended as first-line therapy for symptomatic PVCs in patients with structurally normal hearts 1
• Both American and European guidelines support beta-blockers as initial therapy for symptomatic outflow tract PVCs 1

Atenolol vs. Metoprolol Comparison

• Atenolol superiority: In a randomized, double-blind, placebo-controlled study of 52 patients with symptomatic ventricular arrhythmias, atenolol significantly decreased:

  • Symptom frequency (p=0.03)
  • PVC count (p=0.001)
  • Placebo had no effect on PVC count (p=0.78) or heart rate (p=0.44) 1

• Metoprolol limitations:

  • Demonstrated only "modest efficacy" in suppressing right ventricular outflow tract (RVOT) PVCs 1
  • Recent research shows metoprolol succinate has poor efficacy with only 11.3% of patients achieving "good response" (≥80% PVC reduction) 2
  • Concerning "proarrhythmic" response (>50% increase in PVCs) observed in 25.3% of patients treated with metoprolol succinate 2

Treatment Algorithm for PVCs

1. Initial assessment:

   • Confirm PVCs are idiopathic (structurally normal heart)
   • Assess symptom severity and PVC burden

2. First-line therapy:

   • Atenolol (starting dose 25-50mg daily, titrate as needed)
   • Monitor for efficacy in reducing symptoms and PVC burden

3. If atenolol ineffective or not tolerated:

   • Consider non-dihydropyridine calcium channel blockers (verapamil) 1
   • Consider class IC antiarrhythmics (flecainide has shown superior efficacy compared to other options) 3

4. For refractory cases:

   • Catheter ablation should be considered for patients with:
     • Persistent symptoms despite medication
     • Medication intolerance
     • Patient preference 1
   • Ablation has demonstrated higher long-term efficacy (88%) compared to medications 4

Important Clinical Considerations

• Avoid metoprolol in patients with high PVC burden: Patients with ≥16% PVC burden show poor response to metoprolol with 95.5% having poor/proarrhythmic responses 2

• Proarrhythmic potential: Be aware that beta-blockers, particularly metoprolol succinate, may paradoxically increase PVC burden in some patients, especially those with lower baseline PVC burden (≤10%) 2

• Predictors of good response: Patients with higher baseline daily heart rates may respond better to beta-blocker therapy 2

• Long-term efficacy: While beta-blockers can provide initial symptom relief, their long-term efficacy for PVC suppression is limited compared to catheter ablation 4

By following this evidence-based approach, clinicians can optimize treatment outcomes for patients with symptomatic PVCs, prioritizing mortality, morbidity, and quality of life improvements.