Atrial flutter is an abnormal, rapid heartbeat that produces a "sawtooth" pattern on an electrocardiogram.
Atrial flutter is a heart disorder in which the heart beats much faster than normal.
The condition is similar to atrial fibrillation (afib) — the most common type of arrhythmia (abnormal heartbeat) — and it can cause similar symptoms and complications.
Atrial flutter is much less common than afib, and people with atrial flutter can also have episodes of afib.
Causes of Atrial Flutter
Normally, your heartbeat begins with an electrical signal that's sent out by the sinus node (or sinoatrial node), a group of cells located in the upper right heart chamber (right atrium).
This signal travels from the right atrium to the left atrium and tells both of these chambers to pump blood into the lower heart chambers (right and left ventricles).
The signal then travels to the atrioventricular node, near the center of the heart, where it is slowed down briefly (or pauses) to allow the ventricles to fill with blood.
It then passes through the ventricles, causing those chambers to pump blood to the rest of the body.
A normal resting heart rate is 60 to 100 beats per minute.
In people with atrial flutter, the heart's electrical signal gets stuck repeating in the right atrium, causing the atria to contract rapidly (about 300 times per minute).
The atrioventricular node can't conduct impulses this quickly, but about half of the signals from the atria still make it to the ventricles, causing the lower heart chambers to pump at about 150 beats per minute, according to a study published in November 2005 in the journal Circulation.
Atrial flutter causes the heart to beat in a fast but regular pattern — unlike afib, which causes a fast and irregular pattern.
Atrial flutter produces a distinctive "sawtooth" pattern on an electrocardiogram (EKG or ECG), a test used to monitor the heart and diagnose heart rhythm disorders.
Like afib, atrial flutter develops from health conditions that affect the heart's internal electrical system.
Atrial Flutter Risk Factors
You're more likely to develop atrial flutter if you have:
- Congestive heart failure
- Rheumatic valve disease
- Congenital heart disease
- Lung disease (including emphysema)
- High blood pressure
- Previous cardiac heart surgery or heart attack
- Thyroid conditions
Symptoms and Complications
Aside from a rapid heart rate, symptoms of atrial flutter include:
- Palpitations (racing, pounding, or fluttering of the heart)
- Chest pain or tightness
- Shortness of breath
- Lightheadedness, dizziness, or fainting
- Low blood pressure
Some people don't experience any symptoms from atrial flutter.
Although the heart beats more rapidly in people with atrial flutter, it doesn't fully contract, and the atria don't empty completely into the ventricles. Blood moves more slowly through the heart and may stagnate, allowing small blood clots to form.
These clots can travel to the brain and block an artery, causing a stroke or a cold arm or leg if, for example, the clots travel to a major artery in your limbs.
Also, in people with atrial flutter, the ventricles don't completely fill with blood and may not pump enough blood to meet the body's needs, resulting in heart failure.
Diagnosis and Treatment
Atrial flutter is diagnosed based on your medical and family history, a physical exam, and an EKG.
If an EKG shows that you have atrial flutter (shown by the "sawtooth" pattern), your doctor may also conduct an ultrasound of your heart (echocardiogram) to evaluate your heart and spot any blood clots.
Treatment of atrial flutter focuses on slowing the heart rate, reducing the risk of stroke, and converting the flutter to a normal rhythm driven by the sinus node.
Several classes of medication can help slow your heart rate, including beta blockers, calcium channel blockers, and digoxin. Blood thinners (anticoagulants) or aspirin can help reduce your risk of blood clots.
A procedure called electrical cardioversion — in which you're given a brief, low-power electrical shock through your chest while under anesthesia — is often used to restore a normal sinus heart rhythm.
Although this treatment is effective, people often experience a return of arrhythmia at some point in the future.
Antiarrhythmic medication, such as sodium-channel or potassium-channel blockers, may help restore a normal rhythm or maintain normal rhythm after electrical cardioversion.
Alternatively, your doctor may advise radio frequency ablation to convert an atrial flutter to normal sinus rhythm.
In this procedure, a surgeon will thread a catheter to your heart and use radio wave energy to create scar tissue that blocks the abnormal electrical pathways involved in atrial flutter.