Emergency Room Management of Atrial Fibrillation
Atrial fibrillation is one of the most common arrhythmias encountered in the emergency room. Serious complications from atrial fibrillation include congestive heart failure, myocardial infarction, and thromboembolism. The management of atrial fibrillation in the emergency setting is to first identify the arrhythmia and then to classify it as symptomatic (hemodynamically unstable) or asymptomatic (hemodynamically stable).
Atrial fibrillation should be suspected in all elderly patients with shortness of breath, dizziness, or palpitations. Additionally, atrial fibrillation should be ruled out in any patient with acute fatigue or worsening of congestive heart failure. The best way to diagnose atrial fibrillation is through the use of an electrocardiogram, or ECG. On ECG atrial fibrillation typically presents as an irregularly irregular rhythm. Or, in other words, it will present with an irregular rate with an R-R that is not predictable, usually absent P waves, a rapid atrial rate (usually between 150-300 bpm), and the presence of f waves (atrial fibrillation waves).
Once atrial fibrillation is diagnosed the next step in the management is to determine the patient’s hemodynamic stability. If the patient has chest pain (angina) or low blood pressure (hypotension) the patient is said to be hemodynamically unstable. In this case electrical cardioversion is indicated and is the treatment of choice. The patient is to be sedated and then shocked until sinus rhythm returns. The practitioner should gradually increase the cardioversion strength by starting at 100 J, increasing to 200 J, then 300 J, and then 360 J.
In the case that the patient is hemodynamically stable emergency management for the patient with atrial fibrillation relies around controlling the ventricular rate, The goal of ventricular rate control is less than 100 beats per minute. This is accomplished through the use of 15 mg of diltiazem (Cardizem) intravenously over two minutes, then 5 to 15 mg per hour via continuous IV infusion. Alternatively, esmolol (Brevibloc), propranalol (Inderal), digoxin (Lanoxin), or verapamill (Calan) may be used.
If the rate-control drug administered converted the patient’s rhythm back to a sinus rhythm then the patient can be discharged to follow-up with their primary care provider or cardiologist. However, in the case that the rate-control drug used does not convert the patient back to sinus rhythm then the practitioner may consider cardioversion. If there are contraindications to cardioversion then long-term anticoagulation must be considered.
Barring any contraindications (such as digitalis toxicity and multifocal atrial tachycardia) the patient should be placed on heparin IV. If the patient’s symptoms have persisted for less than 48 hours medical or electrical cardioversion may be attempted. Electrical cardioversion should follow the same algorithm as stated above. Most commonly, quinidine sulfate (Quinidex) or flecainide (Tambocor) are used for medical cardioversion, however, dofetillide (Tikosyn), ibutilide (Corvert), procainamide, or amiodarone (Cordarone) may be implemented.
If the patient has had symptoms for greater than 48 hours or the duration of symptoms is unknown then the patient must be started on heparin IV, placed on warfarin (Coumadin) for 3 weeks, followed by elective cardioversion. Elective cardioversion is electrical and may or may not include medical cardioversion. If the atrial fibrillation still persists up to this point then long-term anticoagulation therapy must be considered.