Atrial flutter is an abnormality in the beating of the heart. Such abnormalities, whether in the rhythm or speed of the heartbeat, are known as arrhythmias.
- Each beat of the heart is a very rapid series of two contractions.
- The first contraction is in the upper chambers, the atria; the second contraction is in the lower chambers, the ventricles.
- The atria receive blood back into the heart and pump it into the ventricles; the ventricles pump the blood out into the aorta, which feeds all the blood vessels to the body.
The beating of the heart is controlled by electrical impulses.
- Under normal circumstances, these impulses are generated by the heart's "natural pacemaker," the sinoatrial (SA) or sinus node, which is located in the right atrium.
- The impulse travels across the atria, generating a contraction.
- It pauses very briefly at the atrioventricular (AV) node, which is located in the upper part of the muscular wall between the two ventricles. This delay gives the blood time to move from the atria to the ventricles.
- The impulse then moves down and through the ventricles, generating the second ventricular contraction that pumps the blood out of the ventricles.
Atrial flutter occurs when an abnormal conduction circuit develops inside the right atrium, allowing the atria to beat excessively fast, about 250-300 beats per minute.
- These rapid contractions are slowed when they reach the AV node, but are still too fast (typically about 150 beats per minute, or every other atrial beat getting through the AV node to the ventricles).
- This type of rhythm is called tachycardia. Because atrial flutter comes from the atria, it is called a supraventricular (above the ventricles) tachycardia.
The main danger of atrial flutter is that the heart does not pump blood very well when it is beating too fast.
- Vital organs such as the heart muscle and brain may not get enough blood.
- This can cause them to fail.
- Congestive heart failure, heart attack, and stroke all can result.
Atrial flutter can come and go; it is then known as paroxysmal atrial flutter. An episode of atrial flutter usually lasts hours or days. Less often, atrial flutter is more or less permanent and is known as persistent atrial flutter.
With proper treatment, atrial flutter is rarely life threatening. Complications of atrial flutter can be devastating, but they usually can be prevented with treatment.
Atrial Flutter Causes
Atrial flutter may be caused by abnormalities or diseases of the heart, by a disease elsewhere in the body that affects the heart, or by consumption of substances that change the way electrical impulses are transmitted through the heart. In some people, no underlying cause is ever found.
Heart diseases or abnormalities that can cause atrial flutter include the following:
- Decreased blood flow to the heart (ischemia) due to coronary heart disease, atherosclerosis, or a blood clot
- High blood pressure (hypertension)
- Disease of the heart muscle (cardiomyopathy)
- Abnormalities of the heart valves (especially the mitral valve)
- An abnormally enlarged chamber of the heart (hypertrophy)
- After open heart surgery
Diseases elsewhere in the body that affect the heart include the following:
- Overactive thyroid gland (hyperthyroidism)
- Blood clot in a blood vessel in the lungs (pulmonary embolism)
- Chronic (ongoing, long-term) lung diseases (COPD), such as emphysema, that lower the amount of oxygen in the blood
Substances that may contribute to atrial flutter include the following:
- Alcohol (wine, beer, or hard liquor)
- Stimulants such as cocaine, amphetamines, diet pills, cold medicines, even caffeine
Atrial Flutter Symptoms
Some people have no symptoms at all with atrial flutter. Others describe the following symptoms:
- Palpitations (rapid heartbeat or a pounding sensation in the chest)
- A "fluttering" or tremor-like feeling in the chest
- Shortness of breath
People with underlying heart or lung disease who experience atrial flutter may have these and other, more significant symptoms:
When to Seek Medical Care for Atrial Flutter
If you experience any of the symptoms of atrial flutter, call your health care provider for an appointment.
If you have been diagnosed and are being treated for atrial flutter, go immediately to a hospital emergency department if you experience any of the following symptoms:
Atrial Flutter Exams and Tests
Upon hearing your symptoms, your health care provider (whether a primary care provider or the provider in the emergency department) will probably suspect an arrhythmia. Because other conditions can cause similar symptoms, the evaluation will at first focus on ruling out the most dangerous ones. Fortunately, there is one simple test that can tell quite a lot about what is happening with the heart: Electrocardiogram (ECG).
The ECG measures and records the electrical impulses that control the beating of the heart.
- The ECG highlights irregularities in these impulses and abnormalities in the heart.
- In arrhythmias, the ECG tracings can help pinpoint the type of arrhythmia and where in the heart it comes from.
- ECG also shows signs of heart attack, heart ischemia, conduction abnormalities, abnormal heart enlargement (hypertrophy), and even certain chemical abnormalities in the heart tissue such as potassium and calcium.
People sometimes have symptoms suggesting atrial flutter, but their ECG result in the emergency department or medical office is normal.
- This does not necessarily mean that you are "imagining things." It may mean that your arrhythmia comes and goes, a very common condition. It may also mean you just have some premature beats, which is not dangerous.
- If this happens to you, you may be asked to undergo an ambulatory ECG.
- The purpose of an ambulatory ECG is to get documentation of whether you do or do not have a significant arrhythmia and what type.
- This is important because you cannot receive treatment until your specific arrhythmia type has been identified.
Ambulatory ECG involves wearing a monitoring device for a few days while you go about your normal activities.
- The device, also known as a Holter monitor, is usually worn around your neck. ECG electrodes are worn on the chest.
- Typically, the device records your heart rhythm on a continual basis for 24-72 hours.
- Some health care providers prefer that you wear the device for a longer time, with intermittent recording of your heart rhythm. This is called an event recorder, which you can turn on when you feel something abnormal. More rarely, an event recorder can be implanted under the skin and worn for several weeks or months.
- Either method works well. The important thing is to get ECG documentation of your arrhythmia.
- This test is done to identify heart valve problems, check ventricular function, or look for blood clots in the atria.
- This very safe test uses the same technique used to check a fetus in pregnancy.
- This test is not always done in the emergency department.
Occasionally, atrial flutter is detected in people with no symptoms when they are seeing their health care provider about something else. The health care provider may notice unusual heart sounds or pulse on physical exam and perform an ECG.
Atrial Flutter Treatment
Control rate: The first treatment goal is to control the ventricular rate.
- If you experience serious symptoms, such as chest pain or congestive heart failure related to the ventricular rate, the health care provider in the emergency department will decrease your heart rate rapidly with IV medications or electrical shock (called cardioversion or defibrillation).
- If you have no serious symptoms, you may be given medications by mouth.
- Sometimes you may require a combination of oral drugs to control your heart rate.
- Surgery may be done to control heart rate or rhythm, but this is rare.
Restore and maintain normal sinus rhythm: Some people with newly diagnosed atrial flutter convert to normal sinus rhythm spontaneously in 24-48 hours. The goal of treatment is to convert the atrial flutter to normal sinus rhythm and prevent recurrence of atrial flutter.
- Not everyone with atrial flutter needs anti-arrhythmic medication.
- The frequency with which your arrhythmia returns and the symptoms it causes partly determine whether you receive anti-arrhythmic drugs.
- Medical professionals carefully tailor each person's anti-arrhythmic medication(s) to produce the desired effect without creating unwanted side effects, some potentially lethal.
Prevent future episodes: This is usually done by taking daily medication to keep the heart at a safe and comfortable rate.
- Coexisting medical conditions, such as congestive heart failure and mitral valve disease, significantly increase the risk of stroke.
- Patients with persistent atrial flutter need a "blood-thinning" drug called warfarin to lower this risk. Warfarin blocks a certain factor in the blood that promotes clotting. Other blood thinners called Pradaxa (dabigatran), Eliquis (apixaban), and Xarelto (rivaroxaban) have been approved by the FDA to prevent stroke in people with atrial fibrillation.
- People at lower risk of stroke and those who cannot take warfarin may use aspirin. Aspirin is not without its own side effects, including bleeding problems and stomach ulcers.
Atrial Flutter Care at Home
Most people known to have atrial flutter will be taking prescribed drugs. Avoid taking any stimulants, and consult with your health care provider before taking any new medications, herbs, or supplements.
Medical Treatment for Atrial Flutter
The first step in treatment is to restore normal rate and sinus rhythm. There are two ways to do this, with medication or with defibrillation.
Defibrillation: This technique uses electrical current to "shock" the heart back to normal sinus rhythm. This is sometimes called "DC cardioversion."
- This is done by applying a device called an external defibrillator to the chest.
- This device uses the paddles familiar to watchers of television medical dramas.
- When this is done in a hospital, usually a mild general anesthetic is given first because the electrical shocks are painful.
- Cardioversion works very well; more than 90% of people convert to sinus rhythm. For some, however, this is not a permanent solution; the arrhythmia comes back.
- Cardioversion increases the risk of stroke and thus, if time allows, requires pretreatment with a blood thinning drug.
- The abnormal pathway(s) is found, and a catheter is placed at this precise location in the conduction system.
- After proper placement, the catheter delivers radiofrequency energy, which burns ("ablates") a portion of the abnormal electrical conduction pathway. This inactivates the abnormal pathway to provide more consistent flow of electrical impulses.
- This technique is low risk; it works in some people but not all. It has few complications and, unlike surgery, requires little recovery time.
Atrial Flutter Medications
The choice of medication depends on the frequency of atrial flutter, the underlying cause, your other medical conditions and overall health, and the other drugs you take. The classes of medications used in atrial flutter are as follows:
- Anti-arrhythmic medications: These drugs are used to chemically convert atrial flutter to normal sinus rhythm, reduce the frequency and duration of atrial flutter episodes, and prevent future episodes. They are often given to prevent return of atrial flutter after cardioversion. Examples are amiodarone, sotalol, ibutilide, propafenone, and flecainide.
- Digoxin (Lanoxin): This drug decreases the conductivity of electrical impulses through the SA and AV nodes, slowing down the heart rate.
- Beta-blockers: These drugs decrease the heart rate by slowing conduction through the AV node, plus they have a direct anti-arrhythmic effect on the atria.
- Calcium channel blockers : These drugs also slow down the heart rate by slowing conduction through the AV node.
- Anticoagulants: These drugs reduce the ability of the blood to clot, thus reducing the risk of an unwanted blood clot forming in the heart or in a blood vessel. Atrial flutter increases the risk of forming such blood clots.
Next Steps and Beyond
Atrial flutter increases your risk of having a stroke.
- When the heart is not pumping properly, blood that is moving more slowly than normal is more likely to clot.
- A piece of a blood clot in the heart can break off and travel to the brain. There, it can block a blood vessel, causing a stroke.
The other serious complication of atrial flutter is heart failure.
- Rapid beating of the heart over a long time can weaken the heart muscle. This further impairs its pumping ability.
- Heart failure describes a condition in which the heart can no longer pump enough blood to the body through the blood vessels.
If you experience atrial flutter and are found to have no underlying heart disease, your outlook is generally quite good. If it occurs once without serious heart or lung disease, most likely you will never have it again. If you do have underlying heart disease, your atrial flutter may recur. Therefore, you should see a heart specialist (cardiologist).
Media file 1: A 12-lead electrocardiogram demonstrating atrial flutter.