Diagnostic criteria

  This is a regular atrial arrhythmia with an atrial rate of 250-350/minute.

  There is no isoelectric baseline between atrial deflections (P waves).

      The high rate of atrial deflections result in
sawtooth appearance.

  Flutter waves are best seen in leads II, III and aVF.

  All of the flutter waves cannot be conducted to the ventricles.

      Usually there is a 2:1, 3:1 or 4:1 AV block.

      Sometimes the block may vary spontaneously.

  Even though the block may vary, atrial flutter is still accepted as a regularly irregular arrhythmia

      since the block is not completely irregular.



Clinical significance

  Holter recordings may show alternating attacks of atrial flutter and atrial fibrillation in the same patient.

  The ventricular rate is expected to be low in patients receiving high dose digoxine, amiodarone

      or beta blocker therapy.

  The pharmacological control of ventricular rate is more difficult in atrial flutter than atrial fibrillation.

  Atrial flutter usually occurs in subjects with organic heart diseases.

      On the other hand, atrial fibrillation may be seen in patients without organic heart diseases.

  Atrial flutter is less common than atrial fibrillation in adults but more common in children.





ECG 1a. The rhythm strip in a patient with atrial flutter just before electrical cardioversion.
Flutter waves are best seen in lead aVF.

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ECG 1b. The ECG of the same patient immediately after successful electrical cardioversion with biphasic 200 Joules.

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ECG 2. On Holter recordings, the flutter waves (sawtooth appearance) may not always be easy to recognize.
This is the Holter recording of the patient whose ECGs before and after the electrical cardioversion are depicted above.

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ECG 3. Atrial flutter with variable block in a mitral stenosis patient under beta blocker therapy.

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ECG 4. Atrial flutter in a patient with permanent cardiac pacemaker.
Red arrows show flutter waves.

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ECG 5. Atrial flutter. Isoelectric baseline is not observed in leads II, III and aVF due to flutter waves.

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ECG 6a. Atrial flutter with 2:1 block.
Flutter waves are best seen in leads II and aVF. Isoelectric baseline is not seen in lead D2.
Flutter waves are not clearly seen in chest leads.

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ECG 6b. 4:1 block is observed in the same patient on another day. The block became
2:1 for only once.
Since the block has increased to 4:1,
flutter waves can be clearly seen in chest leads (C1-C6).

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ECG 7. In this ECG, it is difficult to see the flutter waves at a first glance. The regular and rapid
flutter waves in C1 confirm that
the rhythm is atrial flutter.
Some flutter waves are not seen since they coincide with the QRS complexes.

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ECG 8. Atrial flutter. The block varies regularly.

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ECG 9a. Atrial flutter with 2:1 AV block. The patient complains of fatigue but not palpitation.
Heart rate is about 155/minute.

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ECG 9b. Two hours after ingestion of 80 mg of Sotalol, the block level is increased. At times, the AV block becomes
3:1 or 4:1.

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