Target heart rate in heart failure with reduced ejection fraction and atrial fibrillation: Goldilocks zone

Area of Science:

• Cardiology
• Clinical Trials
• Heart Failure Research

Background:

• Atrial fibrillation (AF) and heart failure with reduced ejection fraction (HFrEF) are increasingly prevalent comorbidities.
• Lower heart rates (HR) in HFrEF are linked to reduced morbidity and mortality, potentially via mechanisms like improved diastolic filling time.
• Current guidelines present a dilemma for HR control in patients with both AF and HFrEF, balancing potential benefits of lower rates against physiological needs.

Purpose of the Study:

• To address the conundrum of optimal heart rate (HR) control in patients with both atrial fibrillation (AF) and heart failure with reduced ejection fraction (HFrEF).
• To review existing evidence and highlight the need for dedicated randomized controlled trials investigating HR control strategies in this specific patient subgroup.

Main Methods:

• Review of existing literature, including landmark trials like RACE II and retrospective analyses of HFrEF trials (CHARM, PARADIGM, ATMOSPHERE).
• Analysis of physiological considerations for HR control in AF and HFrEF.
• Examination of prognostic markers and their impact on the association between HR control and outcomes.

Main Results:

• The RACE II trial suggested a lenient HR control strategy (<110 bpm) is safer and more attainable than strict control (<80 bpm) in permanent AF.
• Retrospective analyses of HFrEF trials hint at better outcomes with less stringent HR targets in AF patients, but this association diminishes after adjusting for prognostic factors.
• No definitive evidence from dedicated trials exists for optimal HR control in the combined AF and HFrEF population.

Conclusions:

• There is a significant need for dedicated randomized controlled trials to determine the optimal rate control strategy for patients with both AF and HFrEF.
• Effective anticoagulation and guideline-directed medical therapy remain crucial, irrespective of the chosen HR control strategy.
• The complex interplay between AF, HFrEF, and HR requires further research to optimize patient outcomes.