What is atrial flutter?
Atrial flutter is an abnormal, rapid heart rhythm that comes from the heart’s upper chambers — the atria — causing them to beat at rates of 220 to 300 times a minute. Atrial flutter is uncommon in the young except when there is a history of heart surgery involving the atria. The operations associated with resulting atrial flutter include the Fontan procedure, Mustard or Senning procedure, repair of tetralogy of Fallot, repair of total anomalous venous connection, and repair of atrial septal defect. The incidence of atrial flutter increases over time after these operations. Click here to learn more about the normal heart rhythm. Atrial flutter occurs when an electrical impulse travels in a circle around the atria like "a dog chasing its own tail." This happens when there are areas of slow and fast conduction in the atria, which is quite common after having surgery in this area. In most people with atrial flutter, the AV node blocks many of the atrial beats from reaching the heart’s lower chambers-the ventricles. Therefore, even though the atria are going 300 beats a minute, the actual ventricular heart rate (which causes the "pulse") is usually between 110 and 150 beats per minute.
How does this problem affect my child's health?
Symptoms of atrial flutter include palpitations (a sensation of rapid or "skipping" heart beats), dizziness, fainting, and fatigue. Although the symptoms can be quite alarming to the child and parents, this is generally not a life-threatening problem. The episodes vary in frequency and severity. They can occur rarely or very often. They can be short, ending on their own, or can persist for long periods of time or until treated. Although there are many treatment options for atrial flutter, the problem can be difficult to "cure" and if the episodes occur often, it can be a very frustrating problem for patients and families. If the episodes occur often or are long-lasting, there is an increased risk that blood clots will form in the heart and, if dislodged, they could cause a stroke. In this case, blood thinners, such as aspirin or warfarin are used to prevent clots from forming. In some people, atrial flutter occurs only once in a while and may even stop on its own. In other people, it occurs often and does not self-convert without medical treatment. Atrial flutter rarely occurs in infants with otherwise normal hearts but when it does it usually resolves within the first year of life. It also rarely occurs during childhood or the teen-age years (except when there are other heart problems as well).
How is this problem diagnosed?
Symptoms: Symptoms caused by atrial flutter include a feeling of "heart racing" along with dizziness, lightheadedness, low energy levels, chest pain, shortness of breath, and/or fainting. Sometimes the person can have very mild or no symptoms. The episodes can vary both in frequency and duration and may or may or may not be related to exercise. Physical findings: If the child has other heart problems, the physical findings that go along with that problem. Otherwise, the physical exam is usually normal. If the child is having an episode at the time of the examination, the pulse rate will be fast. Medical tests: One of the first tests usually done is an electrocardiogram. This is a safe and painless test that involves putting some stickers across the chest. The stickers are connected to a machine that records the heart’s electrical activity. If the child is having an episode during the ECG, the heart rate will be fast and there will be many extra "p" waves from rapid atrial contractions. In order to diagnose atrial flutter, an ECG at the time of symptoms is often needed. If the symptoms don’t occur regularly, this may be done using a small device called a transtelephonic ECG recorder. These devices can be used at home or at school to record an ECG at the time of symptoms. The tracing is held in the device’s memory until it can be sent over the phone to a cardiology center. Other useful tests include a Holter monitor, echocardiogram, and/or an exercise test. If further information is needed, a special type of heart catheterization called an electrophysiologic study may be done.
How is the problem treated?
Treatment of atrial flutter is based on the frequency and severity of the episodes. Possible treatments include electrical conversion by pacing or cardioversion (shock), medications, radiofrequency ablation and pacemaker implantation. In some patients, surgery may be needed. For patients who have rare but long episodes of atrial flutter, treatment may consist of electrical conversion either by pacing the heart at a fast rate or by cardioversion on an as-needed basis. These treatments restore normal heart rhythm by sending extra electrical impulses into the flutter circuit. This acts to block one part of the circuit so the impulse cannot progress beyond that point allowing the heart’s normal rhythm to resume. Pacing does this by delivering a series of small pulses of energy to the heart at a rate slightly faster than the flutter rate. If the person already has a permanent pacemaker, it may be programmed for this purpose (if there is a lead in the heart’s upper chambers). Pacing can also be done by passing a thin catheter (tube) placed down the esophagus (the tube that takes food from the mouth to the stomach). The esophagus passes very close to the heart so that the energy delivered by the catheter can easily reach the heart. Cardioversion (shock) involves giving a larger pulse of energy to the heart via electrode patches placed on the chest. Sedation or anesthesia is used to prevent pain that would otherwise occur with this procedure. Radiofrequency ablation is another treatment for patients who have frequent episodes of atrial flutter. This procedure is done during a special type of heart catheterization called an electrophysiologic study. First, the person is given IV sedation or general anesthesia. Then soft, thin plastic tubes (catheters) are placed in the large blood vessels near the groin and are then gently guided or "floated" to the heart. These catheters are used to locate or "map" the site of the flutter circuit within the atrium. Once the circuit is found, a special type of catheter is used to deliver radiofrequency energy in that spot. The energy heats the catheter tip causing a small "burn" thus interrupting the abnormal circuit. Atrial flutter often occurs in people who have another heart rhythm problem called sick sinus syndrome. The heart beat usually starts in the heart’s natural pacemaker, called the sinus node. Sometimes the sinus node is not healthy so it fires too slowly or irregularly. A slow, irregular rate is known to increase the chances of atrial flutter and may be treated a permanent pacemaker. Some newer pacemakers can detect atrial flutter and treat it by giving a series of paced beats at a rapid rate. Medications used to treat or control atrial flutter include sotalol, amiodarone, digoxin, propafenone, and beta blockers. Sometimes people with complex heart problems have frequent episodes of atrial flutter that are not improved by the treatments outlined above. In some of these patients surgery may be needed. This usually pertains to patients after the Fontan or Mustard procedures or valve replacement surgery. Sometimes revising parts of the initial surgery can decrease the number of episodes of atrial flutter. There is also an operation called the Maze procedure that was designed to surgically prevent atrial flutter. In this operation, carefully placed incisions (cuts) are made in the atrium (heart’s upper chambers) and then stitched closed. These cuts heal creating long lines of scar tissue or block that physically interrupt possible flutter circuits.
Clinics
Care and services for patients with this problem are provided in the Congenital Heart and Cardiovascular Surgery clinics at the University of Michigan Medical Center in Ann Arbor.
What is the outlook for children with atrial flutter?
Overall, the outlook for people with atrial flutter is very good. In general, it is not a life-threatening problem and there are many available treatments. Finding the best treatment often requires a trial-and-error approach and this can be very frustrating for children and families. In young people, atrial flutter occurs most often many years after surgery for complex heart disease, and can be very disruptive for the young person trying to participate fully in school and work activities and to achieve valued life goals. Support from parents, health care providers, and community members is very important to assist the child through these challenging demands.
References
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