RACE Trial Outcome: Rate Control Strategy for Persistent Atrial Fibrillation
Rate control is non-inferior to rhythm control for preventing cardiovascular death and morbidity in patients with persistent atrial fibrillation, making it an acceptable primary treatment strategy for most patients. 1
Key RACE Trial Findings
The RACE trial enrolled 522 patients (mean age 68 years) with persistent AF or flutter lasting less than 1 year who had undergone 1-2 cardioversions over 2 years. 1 The primary composite endpoint included cardiovascular death, heart failure, severe bleeding, pacemaker implantation, thromboembolic events, and severe adverse drug effects. 1
After 2.3 years of follow-up, the rate control group had significantly better outcomes: 17.2% (44/256 patients) experienced the primary endpoint compared to 22.6% (60/266 patients) in the rhythm control group (p=0.11). 1 This demonstrated that rate control was not inferior to rhythm control for preventing death and morbidity. 1
Clinical Implications for Treatment Strategy
When to Choose Rate Control as Primary Strategy
Rate control should be the initial approach for:
- Elderly patients (≥65 years) with persistent AF who have hypertension or heart disease 1
- Patients with minimal symptoms (EHRA score 1) despite AF 2
- Patients with multiple cardiovascular comorbidities or uncontrolled hypertension 2
- Older patients whose symptoms are adequately controlled with rate management 1
The ACC/AHA/ESC guidelines explicitly state that rate control with chronic anticoagulation is the recommended strategy for the majority of patients with atrial fibrillation. 1
When Rhythm Control Remains Appropriate
Consider rhythm control for:
- Younger patients with highly symptomatic AF (EHRA score >2) despite adequate rate control 2
- Patients with paroxysmal lone AF and minimal structural heart disease 1
- Hemodynamically unstable patients with AF causing hypotension or worsening heart failure requiring urgent cardioversion 1
- Patients with reversible AF triggers (thyrotoxicosis, post-cardiac surgery) 1
Critical Anticoagulation Mandate
Anticoagulation decisions must be based on stroke risk factors (CHA₂DS₂-VASc score), not on whether rate or rhythm control is chosen. 1, 2 This is a crucial finding from RACE and AFFIRM trials. 1
The RACE trial demonstrated that 21 of 35 thromboembolic complications occurred in the rhythm control group, with the majority happening during inadequate anticoagulation. 3 Most strokes in AFFIRM occurred either during subtherapeutic INR or after warfarin cessation. 4 Clinically silent AF recurrences can occur even with antiarrhythmic drugs, making continued anticoagulation essential for high-risk patients regardless of apparent rhythm control. 1, 5
Rate Control Target Goals
Initial target: Resting heart rate <110 bpm (lenient control). 5 This approach is non-inferior to strict control for mortality, heart failure hospitalization, and stroke. 5
Stricter control (60-80 bpm at rest, 90-115 bpm during moderate exercise) should be reserved for patients with persistent AF-related symptoms despite lenient control. 1, 5 The AFFIRM trial defined adequate control as average heart rate up to 80 bpm at rest and either average rate up to 100 bpm over 18-hour Holter monitoring or maximum 110 bpm during 6-minute walk test. 1
Post-hoc analysis of RACE showed no difference in cardiovascular morbidity, mortality, or quality of life between patients with mean heart rates <80 bpm versus ≥80 bpm during follow-up. 6
Pharmacological Implementation
For patients with preserved left ventricular function: Beta-blockers, diltiazem, verapamil, or digoxin as first-line agents. 5
For patients with reduced left ventricular function or heart failure: Beta-blockers and/or digoxin; avoid non-dihydropyridine calcium channel blockers. 1, 5
For acute rate control without hypotension/heart failure: Intravenous beta-blockers (esmolol, metoprolol, propranolol) or non-dihydropyridine calcium channel antagonists (verapamil, diltiazem). 1
For acute rate control with heart failure or hypotension: Intravenous digoxin or amiodarone. 1, 2
Common Pitfalls to Avoid
Never use AV nodal blocking agents in Wolff-Parkinson-White syndrome with AF, as they can facilitate dangerous antegrade conduction along the accessory pathway. 5
Never discontinue anticoagulation in high stroke-risk patients simply because rate control is achieved, as stroke risk persists regardless of ventricular rate control. 5, 3
Do not assume rhythm control eliminates stroke risk—the rhythm control group in RACE had more thromboembolic events, particularly when anticoagulation was inadequate. 3
Quality of Life and Hospitalization
The RACE trial found no significant differences in quality of life between rate and rhythm control strategies. 1 However, hospitalization was more frequent in rhythm control arms across all major trials, primarily due to admissions for cardioversion. 1
Heart failure development occurred at similar rates (3.5% rate control vs 4.5% rhythm control in RACE) without significant differences between strategies. 1