What is the optimal resting heart rate for a patient with heart failure and reduced ejection fraction (HFrEF) on beta-blocker therapy, such as metoprolol succinate?

Optimal Resting Heart Rate for HFrEF Patients on Beta-Blockers

The optimal resting heart rate for patients with heart failure and reduced ejection fraction (HFrEF) on beta-blocker therapy should be less than 70 beats per minute, with target doses of beta-blockers being the primary goal rather than achieving a specific heart rate.

Evidence-Based Recommendations for Heart Rate Control in HFrEF

Target Heart Rate

• Current evidence suggests that a resting heart rate <70 beats per minute is associated with better outcomes in HFrEF patients 1, 2
• The European Society of Cardiology (ESC) guidelines indicate that heart rates between 60-100 beats/min are acceptable for patients with heart failure and atrial fibrillation, though rates <70 beats/min may be associated with worse outcomes in this specific population 3
• For patients in sinus rhythm, lower heart rates correlate with better outcomes, particularly when achieved through appropriate beta-blocker dosing

Beta-Blocker Dosing Strategy

1. Focus on target dose rather than heart rate alone:

   • The MERIT-HF study found that the risk-reducing effect of metoprolol CR/XL was independent of baseline heart rate, achieved heart rate, or change in heart rate 4
   • The primary goal should be to reach target beta-blocker doses used in clinical trials, regardless of baseline or achieved heart rate 4

2. Recommended beta-blockers and target doses:

   • Only use evidence-based beta-blockers proven to reduce mortality in HFrEF 3:
     • Bisoprolol (target: 10 mg daily)
     • Carvedilol (target: 25-50 mg twice daily)
     • Metoprolol succinate (target: 200 mg daily)

3. Titration protocol:

   • Start at a low dose and gradually increase every 2 weeks as tolerated 3
   • For metoprolol succinate, start at 12.5-25 mg daily and titrate to target dose of 200 mg daily 3
   • Avoid initiating beta-blockers in decompensated patients or those requiring inotropic support

Clinical Reality vs. Targets

• Real-world data shows that most HFrEF patients (55-71%) have resting heart rates ≥70 beats/min despite beta-blocker therapy 1, 5
• Only a minority of patients achieve target beta-blocker doses in clinical practice:
  • 19% for carvedilol
  • 5% for metoprolol succinate
  • 15% for bisoprolol 1

Special Considerations

Contraindications and Cautions

• Do not initiate beta-blockers when heart rate <45 beats/min 6
• Use caution in patients with:
  • Second or third-degree heart block
  • Significant first-degree heart block (PR interval ≥0.24 sec)
  • Systolic blood pressure <100 mmHg
  • Moderate-to-severe cardiac failure decompensation 6

Additional Therapies for Rate Control

• For patients who remain symptomatic with heart rate ≥70 beats/min despite maximally tolerated beta-blocker therapy:
  • Consider adding ivabradine (particularly for patients in sinus rhythm) 3
  • For patients with atrial fibrillation and HFrEF, beta-blockers should be considered for rate control 3

Practical Algorithm for Heart Rate Management in HFrEF

1. Initial assessment:

   • Document baseline heart rate and blood pressure
   • Ensure patient is euvolemic before initiating/uptitrating beta-blockers
   • Select an evidence-based beta-blocker (bisoprolol, carvedilol, or metoprolol succinate)

2. Titration phase:

   • Start at lowest dose and double every 2 weeks as tolerated
   • Monitor for hypotension, bradycardia, and worsening heart failure symptoms
   • Continue uptitration until reaching target dose or maximum tolerated dose

3. Maintenance phase:

   • Aim for resting heart rate <70 beats/min if possible
   • If target heart rate not achieved despite maximum tolerated beta-blocker dose:
     • For patients in sinus rhythm: Consider adding ivabradine
     • For patients with atrial fibrillation: Consider adding digoxin

4. Monitoring:

   • Regularly assess heart rate, blood pressure, and symptoms
   • Do not reduce beta-blocker dose solely to achieve a specific heart rate target if the patient is tolerating the medication well

Remember that achieving target doses of beta-blockers is more important than reaching a specific heart rate, as the mortality benefit appears to be related to the dose rather than the achieved heart rate alone.