AFFIRM showed that in older, higher-risk patients with atrial fibrillation, rhythm control did not improve survival compared with rate control. Rate control was at least as good clinically and avoided more hospitalizations and antiarrhythmic drug toxicity.
Study design
- Multicenter, randomized trial
- N = 4,060
- Patients with atrial fibrillation at high risk for stroke or death
- Randomized to rhythm control vs rate control
- Mean follow-up 3.5 years
- Primary outcome: all-cause mortality
Population
Included
- Atrial fibrillation likely to be recurrent
- Age ≥65 years or other risk factors for stroke/death
- Eligible for long-term anticoagulation
- Clinically appropriate for either rate or rhythm strategy
Common risk factors
- Hypertension
- Coronary artery disease
- Heart failure
- Prior stroke/TIA
- Diabetes
Mean age 70
39% women
High stroke risk
Mostly persistent/recurrent AF
Warfarin era
Interventions
Rate control
- Control ventricular rate without routine restoration of sinus rhythm
- Beta-blockers, calcium channel blockers, digoxin, or combinations
- Anticoagulation recommended based on stroke risk
Rhythm control
- Attempt to restore and maintain sinus rhythm
- Antiarrhythmic drugs and cardioversion as needed
- Amiodarone, sotalol, propafenone, flecainide, quinidine, disopyramide, procainamide, or moricizine
Primary outcome
- Primary outcome: all-cause mortality
- 23.8% with rhythm control vs 21.3% with rate control at 5 years
- HR 1.15, 95% CI 0.99-1.34
- P = 0.08
- No survival benefit with rhythm control
Rhythm control vs rate control
All-cause mortality at 5 years
30%
22.5%
15%
7.5%
0%
23.8% vs 21.3% | HR 1.15 | NS
Primary outcome: all-cause mortality. Rhythm control did not improve survival compared with rate control.
Secondary outcomes
| Outcome | Rhythm control | Rate control | Interpretation |
|---|---|---|---|
| All-cause mortality | 23.8% | 21.3% | No significant difference, numerically worse with rhythm control |
| Ischemic stroke | Similar | Similar | Most strokes occurred after warfarin was stopped or INR was subtherapeutic |
| Hospitalizations | More frequent | Less frequent | Rhythm strategy led to more admissions and procedures |
| Adverse drug effects | More frequent | Less frequent | Driven by antiarrhythmic toxicity |
Safety
- Rhythm control exposed patients to more antiarrhythmic drug toxicity.
- Rate control reduced medication burden and hospitalizations.
- Stroke prevention remained critical regardless of strategy.
Practical point: AFFIRM does not mean rhythm control is useless. It means routine rhythm control for survival benefit was not superior in this older, higher-risk AF population. Rhythm control still matters for symptoms, tachycardia-induced cardiomyopathy, difficult rate control, HF, and selected early AF patients.
Interpretation
- Rate control is a reasonable default strategy for many older, minimally symptomatic AF patients.
- Rhythm control did not reduce mortality and caused more hospitalizations and adverse drug effects.
- Anticoagulation should not be stopped just because sinus rhythm appears restored.
- Modern rhythm control has changed with safer ablation strategies and newer trials, but AFFIRM remains foundational for rate vs rhythm decision-making.
Citation: Wyse DG, Waldo AL, DiMarco JP, et al. A Comparison of Rate Control and Rhythm Control in Patients with Atrial Fibrillation. New England Journal of Medicine. 2002;347:1825-1833.
NEJM