What is atrial flutter?
Atrial flutter refers to an arrhythmia, or an abnormal heart rhythm that involves an electrical circuit formed in the atrium, the upper two chambers of the heart. Normal electrical conduction in the heart starts with the generation of electricity in the sinus node in the upper portion of the right atrium. Electricity moves from the sinus node through the atrium. From there, it is transmitted to the AV node to the ventricles. As electricity passes to the ventricles, the heart muscle contracts.
Atrial flutter occurs when electricity forms an abnormal circuit somewhere in the atrium. As electricity moves around the circuit, it generates impulses at a very fast rate. The sinus node is completely shut down in this situation. Usually the heart rate in the atrium is very fast, often in the range of 350-500 beats per minute. Fortunately the AV node is usually incapable of transferring impulses at such a fast rate, so only every other or every third impulse is conducted to the ventricles. This results in a heart rate in the ventricles that is much slower than the atrium, but still usually faster than normal. For example, if the atrium are beating at 360 beats per minute, and only every third beat gets through to the ventricles, the ventricles will beat at 120 beats per minute.
What causes atrial flutter in children?
Atrial flutter in children is seen most commonly in newborn babies. In this setting, it is usually caused by the relative immaturity of the heart's electrical system. It is usually noticed when somebody listens and hears a faster than normal heart rate in an otherwise healthy appearing baby. Although medication may be effective, usually the quickest and most efficient means of treating atrial flutter in a baby involves an electrical cardioversion. In this setting, an electrical shock is delivered to the baby's chest. This momentarily stuns was the heart and resets the electricity completely. The atrial flutter circuit is terminated and the sinus node is able to effectively take over again. Atrial flutter in babies is usually a one-time problem and typically does not recur. Most babies who have atrial flutter are observed for at least 48 hours. If there is no recurrence of the problem during that time frame, it is usually safe to discharge the baby without any medication. Recurrence is very unusual.
Atrial flutter in older children is very uncommon. When it does occur, it is almost always in the setting of surgically repaired heart disease. Scar tissue caused by surgery can create a circuit in which atrial flutter may occur. In this setting, atrial flutter is again treated most effectively with electrical cardioversion. However, as opposed to babies, the likelihood of recurrence is relatively high. Most older children and teenagers who develop atrial flutter require long-term medication.
What are the signs and symptoms of atrial flutter?
The danger of atrial flutter, or any tachycardia for that matter, involves the degree of stress placed on the heart muscle. When the heart rate is very fast, or even when the heart rate is not so fast but continues for a prolonged period of time, the heart muscle tires out. This may lead to ineffective pumping and the development of congestive heart failure. Symptoms of congestive heart failure in babies include rapid breathing, sweating, poor feeding, and poor weight gain. In older children, atrial flutter usually causes symptoms of palpitations. Rarely associated symptoms of chest pain, dizziness, or syncope may occur as well.
How is atrial flutter treated?
The most effective treatment of atrial flutter is electrical cardioversion. In babies this usually is a one-time treatment that solves the problem permanently. In older children, medication is often necessary to prevent recurrence.
In summary, atrial flutter in children is relatively uncommon. Fortunately most cases are treatable with either electrical cardioversion or medication, or a combination of the two.