Heart Failure with Atrial Fibrillation Management

Rate Control

The American College of Cardiology recommends intravenous digoxin or amiodarone to control heart rate in patients with atrial fibrillation and heart failure who don't have an accessory pathway (Level of Evidence: B) 1
The American Heart Association recommends a combination of digoxin and a beta blocker for rate control when single agents are insufficient (Class IIa, Level of Evidence: B) 2
Oral amiodarone may be considered for rate control when heart rate cannot be adequately controlled using a beta blocker or calcium channel antagonist with digoxin (Class IIb, Level of Evidence: C) 2

The American Heart Association advises against using combination therapy in patients with pre-existing bradycardia or heart block without a pacemaker, or WPW syndrome with pre-excited atrial fibrillation (Class III: Harm) 2
Combination therapy with digoxin and amiodarone should be used with caution in patients with significant renal dysfunction, or concurrent use of other medications that can increase digoxin levels, and avoided in patients with pre-existing bradycardia or heart block without a pacemaker, WPW syndrome with pre-excited atrial fibrillation 3, 4, 5
Grapefruit juice should be avoided as it can inhibit amiodarone metabolism, and patients should be aware of potential interactions with other medications, such as tricyclic antidepressants, which can cause marked behavioral changes 5, 6

The following medications may interact with digoxin and require monitoring and potential dose adjustment:

Medication	Recommended Dose Adjustment
Amiodarone	reduce digoxin dose by 30-50%
Dronedarone	reduce digoxin dose by 50%
Verapamil	monitor levels
Clarithromycin	monitor levels
Erythromycin	monitor levels
Itraconazole	monitor levels
Cyclosporine	monitor levels
Propafenone	monitor levels
Flecainide	monitor levels

If digoxin toxicity occurs despite precautions, holding both medications, checking serum digoxin level immediately, and considering digoxin-specific antibody fragments (Fab) for severe toxicity are recommended steps, according to the American College of Cardiology guidelines 3, 4
Sodium bicarbonate (1-2 mEq/kg) may be administered to treat sodium channel blockade effects, and benzodiazepines may be used to control seizures and agitation, as recommended by the American Heart Association 7
For digoxin toxicity with levels >2.0 ng/mL or significant symptoms, digoxin-specific antibody fragments may be required, and monitoring for worsening symptoms and adjusting medication doses accordingly is recommended, considering individual variability in drug metabolism 8, 6, 3
Renal or hepatic impairment may require dose reduction due to altered drug metabolism, as stated by the European Society of Cardiology, and elderly patients are more susceptible to adverse effects at standard doses, according to the American Geriatrics Society 6

The American College of Cardiology recommends reducing digoxin dose by 30-50% and closely monitoring serum digoxin levels when co-administering with amiodarone to prevent toxicity in patients taking both medications 3, 4
Checking serum digoxin levels initially after 7-8 weeks and then every 6 months during continued combination therapy is recommended by the American family physician guidelines to ensure safe co-administration 5
The American College of Cardiology recommends considering digoxin toxicity at levels >2.0 ng/mL, though toxicity can occur at lower levels, and trough serum digoxin level should be 0.5 to 1.0 ng/mL for optimal mortality benefit 3