Rate Control vs. Rhythm Control — When to Choose Each
- Accept atrial fibrillation; control ventricular rate only
- Target: resting rate below 110 beats per minute (lenient); below 80 (symptomatic)
- Favored in: older patients, minimal symptoms, long-standing atrial fibrillation, high drug toxicity risk
- Agents: beta-blockers first-line; diltiazem alternative (avoid in heart failure with reduced ejection fraction); digoxin adjunct
- AFFIRM and RACE trials: no mortality advantage over rate control for rhythm control in older patients
- Restore and maintain sinus rhythm
- Favored in: significant symptoms, newly diagnosed atrial fibrillation (within 1 year), atrial fibrillation-induced cardiomyopathy, younger patients
- EAST-AFNET 4 (2020): early rhythm control within 1 year of diagnosis reduced cardiovascular events
- Drug selection governed entirely by cardiac substrate
- Catheter ablation increasingly preferred in heart failure with reduced ejection fraction
Rhythm Control Drug Selection by Cardiac Substrate
| Cardiac Substrate |
Acceptable Agents |
Contraindicated |
| No structural heart disease |
Flecainide, propafenone, sotalol, dronedarone, amiodarone |
None of the above |
| Coronary artery disease / prior myocardial infarction |
Sotalol, dofetilide, amiodarone; dronedarone (preserved ejection fraction only) |
Flecainide, propafenone |
| Heart failure with reduced ejection fraction |
Amiodarone, dofetilide only |
Flecainide, propafenone, sotalol, dronedarone |
| Left ventricular hypertrophy (wall thickness over 1.4 cm) |
Amiodarone (preferred); sotalol, dofetilide (if corrected QT interval and renal function permit) |
Flecainide, propafenone (relative contraindication) |
Pharmacologic Cardioversion Strategies
Outpatient Strategy
Pill-in-the-Pocket
- Flecainide or propafenone taken by patient at onset of atrial fibrillation episode
- Only in structurally normal hearts with demonstrated in-hospital tolerance
- Mandatory: atrioventricular nodal agent taken 30 to 60 minutes first to prevent 1:1 atrial flutter
- Cardioversion within 2 to 6 hours in majority
Intravenous Acute
Ibutilide
- Intravenous only; effective for recent-onset atrial fibrillation and atrial flutter
- Atrial flutter responds better than atrial fibrillation
- Torsades de pointes risk 4 to 8% -- highest of any cardioversion agent
- Mandatory 4-hour post-dose monitoring; correct electrolytes first
Heart Failure Safe / Multi-Use
Dofetilide and Amiodarone
- Dofetilide: oral cardioversion over 24 to 48 hours; safe in heart failure with reduced ejection fraction; in-hospital initiation
- Amiodarone: less effective acutely but provides simultaneous rate control; safe in structural heart disease; intravenous or oral
Peri-Cardioversion Anticoagulation
Atrial Fibrillation Under 48 Hours
Proceed with Anticoagulation Initiation
- Low immediate thromboembolic risk (insufficient time for thrombus formation)
- Cardioversion may proceed after initiating anticoagulation
- Mandatory: at least 4 weeks post-cardioversion anticoagulation regardless of CHA2DS2-VASc score
- Reason: atrial stunning -- left atrium contracts ineffectively for weeks after cardioversion
Atrial Fibrillation Over 48 Hours or Unknown
Two Accepted Strategies
- Strategy 1: 3 weeks therapeutic anticoagulation before cardioversion, then 4 weeks after
- Strategy 2: transesophageal echocardiogram to exclude left atrial appendage thrombus, then immediate cardioversion, then 4 weeks after
- The 4-week post-cardioversion period is mandatory for both strategies due to atrial stunning
Long-Term Anticoagulation Decision
After the mandatory 4-week post-cardioversion period, continue anticoagulation based on CHA2DS2-VASc score: congestive heart failure (1), hypertension (1), age 75 or older (2), diabetes (1), prior stroke or transient ischemic attack (2), vascular disease (1), age 65 to 74 (1), female sex (1). Treat men with score 2 or more, women with score 3 or more. Prefer direct oral anticoagulants over warfarin for non-valvular atrial fibrillation.