Atrial Flutter

Background

• Atrial flutter (AFL) is a common atrial arrhythmia due to macroreentry around a central obstacle that is either a fixed anatomical structure (such as pulmonary vein) or a functional electrophysiological line of block.
• The macroreentrant circuit in typical or isthmus dependent AFL usually originates in the right atrium and rotates around the anteriorly located tricuspid valve annulus in a counterclockwise direction, whereas the macroreentrant circuits in atypical AFL include various forms that are extremely variable.
• Possible causes for atrial remodeling that lead to AFL include hypertension, prior cardiac surgery, or underlying heart disease.

Evaluation

• Patients with atrial flutter (AFL) may present with a variety of symptoms such as palpitations or chest pain or be asymptomatic.
• Use an electrocardiogram (ECG) for initial testing to diagnose AFL.
• ECG findings of typical flutter include:
  • counterclockwise atrial flutter - classic saw-tooth flutter waves with dominant negative deflection on inferior leads II, III, and aVF
  • clockwise or reverse typical atrial flutter - rounded or bimodal positive atrial deflections in inferior leads II, III, and aVF and bimodal negative wave (forming W shape) in lead V1
  • atrial rates of 240-350 beats/minute with variable block but often 2:1
• ECG findings of atypical flutter are variable and definitive diagnosis is a diagnosis of exclusion after determining the flutter circuit and ruling out cavotricuspid isthmus involvement.
• Consider increasing degree of AV block using vagal maneuvers or IV adenosine when flutter waves are not easily discernible (use adenosine with caution and only when diagnosis necessary due to potential for 1:1 AV conduction and precipitation of atrial fibrillation).
• Consider electrophysiological studies with mapping to confirm underlying flutter mechanism if definitive diagnosis required and to guide catheter ablation therapy.

Management

Acute Management Options

• Anticoagulation therapy recommended using same criteria as atrial fibrillation for patients undergoing cardioversion (electrical or pharmacologic).
• Use synchronized direct current (DC) cardioversion to treat patients with atrial flutter who are hemodynamically unstable or who are symptomatic and rate is hard to control with medications (Strong recommendation).
• Use rate control (IV beta-blockers, diltiazem, or verapamil) as initial strategy if hemodynamically stable (Strong recommendation).
• Consider using IV amiodarone for rate control in selected patients with heart failure where beta-blockers are contraindicated or ineffective and preexcitation is absent (Weak recommendation).
• Use electrical or pharmacologic cardioversion using 1 of the following regimens for patients requiring cardioversion after failed rate control or if rhythm control strategy chosen: (Strong recommendation).
  • IV ibutilide - initial dose 1 mg over 10 minutes if ≥ 60 kg and 0.01 mg over 10 minutes if ≤ 60 kg and subsequent dose 1 mg if arrhythmia does not terminate within 10 minutes
  • oral dofetilide - dose depends on CrCl (500 mcg every 12 hours if CrCl > 60 mL/minute, 250 mcg every 12 hours if CrCl 40-60 mL/minute, 125 mcg every 12 hours if CrCl < 40 mL/minute, and not recommended if CrCl < 20 mL/minute)

Chronic Management Options

• Catheter ablation may be reasonable as initial rhythm control therapy after the first symptomatic episode of atrial flutter (Weak recommendation).
• Perform catheter ablation for patients with recurrent or poorly tolerated atrial flutter (both typical and atypical types) after failed antiarrhythmic drug therapy (Strong recommendation).
• Consider antiarrhythmic drug therapy with amiodarone, dofetilide, or sotalol to maintain sinus rhythm for patients with recurrent atrial flutter if catheter ablation fails or is not desired (choice of antiarrhythmic agent depends on the underlying heart disease and comorbidities) (Weak recommendation).
• Adequate rate control can be difficult to achieve in patients with atrial flutter, but consider beta-blockers, diltiazem, or verapamil if catheter ablation is not feasible or not desired by patient (Weak recommendation).
• Use oral anticoagulant therapy according to the same criteria as atrial fibrillation.