What is pediatric atrial flutter?

Updated: Feb 04, 2019
  • Author: M Silvana Horenstein, MD; Chief Editor: Syamasundar Rao Patnana, MD  more...
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Atrial flutter is an electrocardiographic descriptor used both specifically and nonspecifically to describe various atrial tachycardias. The term was originally applied to adults with regular atrial depolarizations at a rate of 260-340 beats per minute (bpm). Historically, the diagnosis of atrial flutter was restricted to those patients whose surface electrocardiogram (ECG) revealed the classic appearance of "flutter waves." This sharp demarcation is used less frequently in the current era, where the more electrophysiologically descriptive "atrial reentry tachycardia" is used instead.

Atrial flutter is infrequent in children without congenital heart disease. In these patients with otherwise normal cardiac anatomy atrial reentry tachycardias are observed mostly during fetal life in late pregnancy, and during adolescence.

In the fetus, atrial flutter is defined as a rapid regular atrial rate of 300-600 bpm accompanied by variable degrees of atrioventricular (AV) conduction block, resulting in slower ventricular rates.

During this type of tachycardia, the atrial rate is so rapid that normal AV nodes usually display a physiologic second-degree block, with a resultant 2:1 conduction ratio. In individuals with AV nodal disease or increased vagal tone, or when certain drugs are used, higher degrees of AV block may develop, such as 3:1 or higher. In individuals with accessory AV nodal pathways, a 1:1 conduction ratio may occur through the accessory pathway with resultant ventricular rates of 260-340 bpm, which can cause sudden death. A 1:1 conduction ratio may also occur when the atrial rate is relatively slow (eg, < 340 bpm) during atrial flutter or when physiologic processes facilitate AV nodal conduction, such that a rapid ventricular response can still result in sudden death.

Patients who have undergone Mustard, Senning, or Fontan operations are more prone to developing this arrhythmia because of atrial scars from surgery and right atrial enlargement, usually seen after the classic Fontan operation. Similarly, patients who have undergone surgical repair of an atrial septal defect, total anomalous pulmonary venous connection, and tetralogy of Fallot may later develop atrial flutter. [1] Individuals with muscular dystrophies such as Emery-Dreifuss [2] and myotonic dystrophy [3] may also develop atrial flutter, as well as those with dilated, restrictive, and hypertrophic cardiomyopathies.

Treatment of children with atrial flutter depends on the age of presentation and baseline cardiac anatomy. Fetal atrial flutter is usually treated with oral maternal antiarrhythmic agents without need for further intervention if ventricular function is acceptable and if there is no placental edema. Once the baby is born, it usually responds well to oral antiarrhythmic medications and subsequently resolves. In the other age groups and in patients with baseline abnormal cardiac anatomy or surgical scars, it usually recurs. In general, treatment may involve medications, cardiac pacing, cardioversion, radiofrequency catheter ablation, or surgical procedures (see Treatment). Drug therapy of atrial flutter in children can be classified under the 3 broad headings of ventricular rate control, acute conversion, and chronic suppression (see Medication).

See Atrial Flutter and Emergent Management of Atrial Flutter for more information on these topics.

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