Atrial Ectopic Tachycardia

Presentation

This is a relatively rare arrhythmia in the pediatric population. It is by definition a run of more than 3 premature atrial contractions together. The arrhythmia tends to increase in rate over time and also slows down gradually to normal. The so called warm up - cool down phenomenon. The excitable area of the atrium may be a hamartoma.

Mechanism

The ectopic focus in the atrial myocardium depolarizes faster than the sino-atrial node and conducts down the AV node and His-Purkinje system giving a narrow complex tachycardia.

ECG

The p wave morphology depends upon the position of the abnormal focus in the atrium. It often has the appearance of a sinus tachycardia as the RP interval is long compared to the PR interval. Adenosine, when used as a diagnostic test, reveals the rapid atrial depolarisation during the period the AV node is blocked.

Atrial ectopic tachycardia

Management

Drug therapy with digoxin, flecainide and amioderone have all been successful. If the arrhythmia persists then radiofrequency ablation is very efficacious.

Prognosis

Once the arrhythmia is ablated the long term prognosis is excellent.

This page was last edited 14/2/2004

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