Atrial Flutter

Presentation

This usually present in either the fetus or neonate with a rapid heart rate and signs of cardiac failure. It may also occur late following cardiac surgery.

Mechanism

This is considered to be a macro reentrant tachycardia.

The ventricular rate depends upon both the atrial flutter rate (commonly 300 or even as high as 450 in the fetus) and the degree of AV block. In the example below the ventricular rate is half the atrial rate as there is 2:1 AV block (red arrows are flutter waves). A common clinical catch is the postoperative patient with a ventricular rate of 150 bpm who is though to be in sinus tachycardia but who actual has an atrial flutter rate of 300 bmp with 2:1 AV block. Adenosine will reveal the abnormal rhythm if the a flutter wave has been buried in the QRS complex.

Atrial flutter with 2:1 block

Management

If the circulation is acutely compromised then DC cardioversion is appropriate. Chemical cardioversion may sometimes be achieved with Amioderone, sotalol and flecainide and the ventricular response can be slowed using digoxin. Late post operative patients may require radiofrequency ablation.

Prognosis

Presentation as either a fetus or neonate gives a favorable prognosis. Conversion to sinus rhythm is usually relatively easy and frequently flutter does not recur. Post operative patients are far more resistant to treatment.

This page was last edited 14/2/2004

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