Atrial flutter

Atrial flutter is a cardiac arrhythmia characterized by atrial rates of 240-400 beats/min and some degree of atrioventricular (AV) node conduction block. For the most part, morbidity and mortality are due to complications of rate (eg, syncope and congestive heart failure [CHF]).

Essential update: Catheter ablation successfully treats scar-related atypical atrial flutter

With the aid of a combination of high-density activation and entrainment mapping, catheter ablation can be successfully used to treat scar-related atypical atrial flutter or atrial tachycardia, according to a report by Coffey et al.^[1] The retrospective investigation also found that the highest rates of acute and long-term recurrences of atrial tachycardia were in patients with the septal form of the condition.

The study involved 91 consecutive patients with a total of 171 atrial tachycardias.^[1] Irrigated radiofrequency ablation (RFA) of constrained areas along the circuit produced acute success rates of 97% for patients with nonseptal atrial tachycardia and 77% and those with septal atrial tachycardia. Long-term success rates were 82% for patients with nonseptal atrial tachycardia and 67% for those with at least 1 septal atrial tachycardia.

In patients whose atrial tachycardia was associated with previous catheter ablation, cardiac surgery or a maze procedure, or idiopathic atrial scarring, the long-term success rates were 75%, 88%, and 57%, respectively.^[1]

Signs and symptoms

Signs and symptoms in patients with atrial flutter typically reflect decreased cardiac output as a result of the rapid ventricular rate. Typical symptoms include the following:

• Palpitations
• Fatigue or poor exercise tolerance
• Mild dyspnea
• Presyncope

Less common symptoms include angina, profound dyspnea, or syncope. Tachycardia may or may not be present, depending on the degree of AV block associated with the atrial flutter activity.

Physical findings include the following:

• The heart rate is often approximately 150 beats/min because of a 2:1 AV block
• The pulse may be regular or slightly irregular
• Hypotension is possible, but normal blood pressure is more commonly observed

Other points in the physical examination are as follows:

• Palpate the neck and thyroid gland for goiter
• Evaluate the neck for jugular venous distention
• Auscultate the lungs for rales or crackles
• Auscultate the heart for extra heart sounds and murmurs
• Palpate the point of maximum impulse on the chest wall
• Assess the lower extremities for edema or impaired perfusion

If embolization has occurred from intermittent atrial flutter, findings are related to brain or peripheral vascular involvement. Other complications of atrial flutter may include the following:

• CHF
• Severe bradycardia
• Myocardial rate–related ischemia

See Presentation for more detail.

Diagnosis

The following techniques aid in the diagnosis of atrial flutter:

• ECG – This is an essential diagnostic modality for this condition
• Vagal maneuvers – These can be helpful in determining the underlying atrial rhythm if flutter waves are not seen well
• Adenosine – This can be helpful in the diagnosis of atrial flutter by transiently blocking the AV node
• Exercise testing – This can be utilized to identify exercise-induced atrial fibrillation and to evaluate ischemic heart disease
• Holter monitor – This can be used to help identify arrhythmias in patients with nonspecific symptoms, to identify triggers, and to detect associated atrial arrhythmias

Transthoracic echocardiography (TTE) is the preferred modality for evaluating atrial flutter. It can evaluate right and left atrial size, as well as the size and function of the right and left ventricles, and this information facilitates diagnosis of valvular heart disease, left ventricular hypertrophy (LVH), and pericardial disease.

See Workup for more detail.

Management

General treatment goals for symptomatic atrial flutter are similar to those for atrial fibrillation. They include the following:

• Control of ventricular rate – This can be achieved with drugs that block the AV node; intravenous (IV) calcium channel blockers (eg, verapamil and diltiazem) or beta blockers can be used, followed by initiation of oral agents
• Restoration of sinus rhythm – This can be done by means of electrical or pharmacologic cardioversion or RFA; successful ablation reduces or eliminates the need for long-term anticoagulation and antiarrhythmic medications
• Prevention of recurrent episodes or decrease in their frequency or duration – In general, the use of antiarrhythmic drugs in atrial flutter is similar to that in atrial fibrillation
• Prevention of thromboembolic complications – Adequate anticoagulation, as recommended by the American College of Chest Physicians, has been shown to decrease thromboembolic complications in patients with chronic atrial flutter and in patients undergoing cardioversion
• Minimization of adverse effects from therapy – Because atrial flutter is a nonfatal arrhythmia, carefully assess the risks and benefits of drug therapy, especially with antiarrhythmic agents