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PekkaRaatikainen

Treatment of Atrial Flutter

Essentials

  • After atrial fibrillation, atrial flutter is the next most common and significant atrial arrhythmia.
  • The regular sawtooth flutter waves (F waves) of typical atrial flutter can be seen in ECG leads II, III, and aVF (picture 1). The atrial rate is 240-350/min.
  • Antiarrhythmic drugs have proved not to be very effective and, in some cases, even dangerous. Catheter ablation has therefore superseded antiarrhythmic drugs in the prophylactic treatment of typical atrial flutter.
  • Flecainide is commonly used in the treatment of lone atrial fibrillation, but it must be avoided in atrial flutter due to the risk of proarrhythmia (1:1 atrial flutter).

Pathogenetic mechanism

  • The mechanism of atrial flutter is macro-reentrant circuit, and, as in atrial fibrillation, the arrhythmia is induced by atrial ectopic beats.
  • In typical atrial flutter, macro-reentrant circuit occurs in the right atrium.
    • The critical structure as for sustaining the arrhythmia and for consideration of ablative therapy is the isthmus between the tricuspid valve orifice and the inferior vena cava.
  • Atypical atrial flutter denotes macro-reentrant circuit that originates from another site either in the right or left atrium. In this case, the appearance and rate of the atrial waves in the ECG recording will vary depending on the site and size of the arrhythmic loop.
    • Such arrhythmia may occur, for example, after heart surgery involving the atria (”atrial scar macro-reentrant tachycardia”) and after catheter ablation carried out for atrial fibrillation.

Acute care

  • Drugs used to reduce the ventricular rate are the same as used in atrial fibrillation, i.e. beta-blockers, calcium-channel blockers (verapamil, diltiazem) and digoxin (see Management of Acute Atrial Fibrillation). Digoxin may convert atrial flutter to atrial fibrillation which is better tolerated.
  • The first-line treatment for the restoration of sinus rhythm is electrical cardioversion Electrical Cardioversion using a biphasic defibrillator (initial energy level at 100 J), unless there are facilities to attempt cardioversion with atrial overdrive pacing either via a trans-oesophageal electrode or a permanent pacemaker.
  • In a hospital environment, pharmacological cardioversion may be attempted with ibutilide.
    • It is more effective in atrial flutter than in atrial fibrillation and will restore sinus rhythm within less than one hour in about 60% of acute cases.
    • In order to avoid the occurrence of proarrhythmia (torsade de pointes) it must be ensured, before the administration of the medicine, that the patient's serum potassium is above 4.0 mmol/l and that the QT time is not prolonged.
    • The administration of the drug is stopped immediately on the restoration of sinus rhythm.
  • Anticoagulation in association with cardioversion is carried out according to the same principles as in atrial fibrillation Management of Acute Atrial Fibrillation.
  • The use of Class IC antiarrhythmic drug (flecainide) is contraindicated for cardioversion in atrial flutter due to their poor efficacy and the risk of proarrhythmia (1:1 atrial flutter where each atrial impulse is conducted to the ventricles).
  • Vernakalant is not effective for atrial flutter.

Prophylactic treatment

  • The effect of antiarrhythmic drugs in atrial flutter is poor and their use is associated with many adverse effects.
  • The optimisation of the ventricular rate is difficult because in atrial flutter the heart rate typically shows sharp variation due to changes in the atrioventricular conduction; 2:1 conduction may, for example, change to 3:1 conduction and vice versa.
  • Thus, the first-line therapy for prevention of typical atrial flutter consists of catheter ablation, where radiofrequency electrical energy is guided into the heart, via a special catheter, in order to permanently ablate the ”arrhythmia loop” responsible for the flutter.
    • Catheter ablation is successful in almost all cases of typical atrial flutter, and the arrhythmia rarely recurs after the procedure (< 10%).
    • Advanced age, a structural heart defect and chronic atrial flutter are not contraindications for catheter ablation.
    • Isthmus ablation is often also successful in cases where antiarrhythmic medication (e.g. flecainide or amiodarone) has converted atrial fibrillation to atrial flutter.
  • If the patient presents with both atrial fibrillation and flutter, the need for ablation therapy may be assessed with the aid of table T1.
  • Ablation therapy is more difficult in atrial scar tachycardia and in other cases of atypical atrial flutter. Nevertheless, with new mapping methods the treatment results are sufficiently good even in these cases to warrant the referral of patients, whose atrial flutter responds poorly to drug treatment, for a catheter ablation assessment.

Indications for catheter ablation in recurrent typical atrial flutter

Clinical presentationIndication for referral
Typical atrial flutter the sole documented arrhythmiaAlways refer for ablation
More typical atrial flutter than atrial fibrillationRefer for ablation if drug therapy not effective
More atrial fibrillation than typical atrial flutterDrug therapy is the treatment of choice.
Antiarrhythmic medication converts atrial fibrillation to typical atrial flutterRefer for ablation

Anticoagulant therapy

Related Keywords ⬆

ATC Code:

C01BD05

C08DB01

C01BC04

C08DA01

C01BD01

C07AB02

C07AB03

C07AB04

C07AB05

C07AB07

C07AB08

C07AB09

C07AB12

C07AB14

C01AA05

Primary/Secondary Keywords