Management of Acute Atrial Fibrillation
For prevention of atrial fibrillation, see Prevention of Atrial Fibrillation.
Essentials
- In the treatment of acute atrial fibrillation (AF), the choice between rhythm control and rate control as the treatment approach is made on an individual basis (see Treatment Approach for Atrial Fibrillation: Rate Control or Rhythm Control?). At the same it must be ensured that anticoagulation treatment is implemented according to recommendations.
- As a common rule in frequently recurring AF, it is worthwhile to omit cardioversion and to concentrate on rate control if it is not possible to intensify preventive therapy.
- Unless an immediate restoration of sinus rhythm is necessary, the initial treatment of AF should aim to slow the ventricular rate to below 100/min.
- Response is achieved quickly with intravenous administration of an agent that depresses atrioventricular (AV) conduction.
- In 50-70 % of cases, sinus rhythm is restored spontaneously within 24-48 hours with no further intervention required.
- The drug of first choice is usually a beta blocker. They are safe in coronary heart disease and, with correct dosage, also in heart failure. They are also suitable for use in primary care.
- Calcium-channel blockers (verapamil and diltiazem) are well tolerated in lone AF, but they must not be used in heart failure.
- Digoxin is less effective than beta blockers and calcium-channel blockers, and the onset of its action is slower. In severe heart failure (e.g. pulmonary oedema Acute Heart Failure and Pulmonary Oedema), however, it does not lower blood pressure as do beta blockers or calcium-channel blockers.
- Amiodarone may sometimes be used in specialist units to control the rate of ventricular response to AF. Its advantages include little negative inotropic effect and low risk of proarrhythmia, which make it suitable for the treatment of postoperative, critically ill and haemodynamically otherwise unstable patients.
- Dronedarone is contraindicated for rate control in permanent AF.
- The safest treatment option of AF associated with WPW syndrome is electrical cardioversion. If this is not possible, the patient may be given flecainide or amiodarone. These drugs also depress conduction over the accessory pathway.
- Calcium-channel blockers, digoxin and beta blockers favour preferential conduction over the accessory pathway, which is why they must not be used in patients with pre-excited atrial fibrillation.
- A summary of drugs used for ventricular rate control and cardioversion in acute AF is given in table T1.
Dosage of drugs in the management of acute AF. Intravenous administration is recommended in urgent cases.
| Drug | Dosage |
---|
Ventricular rate control |
Beta blockers | Metoprolol | 5 mg by slow intravenous injection, may be repeated 2-3 times at 5 minute intervals |
| |
Esmolol1) | Initially 10-50 mg by rapid intravenous injection, subsequent infusion 1-4 mg/min according to heart rate and blood pressure |
Calcium-channel blockers | Verapamil | 2.5-5 mg by slow intravenous injection, may be repeated if necessary up to a total dose of 10 mg |
Other drugs | Digoxin | 0.25 mg by slow intravenous injection, may be repeated 2-3 times at 1-2 hour intervals (maximum dose 1 mg/24 h) |
Amiodarone1) | Initially 150-300 mg by intravenous infusion over 10-60 minutes, subsequent infusion 1 200-1 800 mg/24 hours |
Cardioversion |
Class IC drugs | Flecainide | 1-2 mg/kg (max 150 mg) by intravenous infusion over 10-30 minutes or 300 mg by mouth as a single dose |
Class III drugs | Amiodarone1) | Initially 150-300 mg by intravenous infusion over 10-60 minutes, subsequent infusion 1 200-1 800 mg/24 hours |
Ibutilide1) | 1 mg by intravenous infusion over 10 minutes, may be repeated once after 10 minutes |
Other drugs | Vernakalant1) | 3 mg/kg (max 339 mg) by intravenous infusion over 10 minutes, after 15 minutes if needed 2 mg/kg (max 226 mg) by intravenous infusion over 10 minutes |