Atrial fibrillation/flutter is a heart rhythm disorder (arrhythmia). It usually involves a rapid heart rate, in which the upper heart chambers (atria) are stimulated to contract in a very disorganized and abnormal manner.
Alternative Names: Auricular fibrillation; A-fib.
To pump blood, your heart muscles must contract and relax in a coordinated rhythm. Contraction and relaxation are controlled by electrical signals that travel through your heart muscle.
Your heart consists of four chambers — two upper chambers (atria) and two lower chambers (ventricles). Within the upper right chamber of your heart (right atrium) is a group of cells called the sinus node. This is your heart's natural pacemaker. The sinus node produces the impulse that starts each heartbeat.
Normally, the impulse travels first through the atria and then through a connecting pathway between the upper and lower chambers of your heart called the atrioventricular (AV) node. As the signal passes through the atria, they contract, pumping blood from your atria into the ventricles below. As the signal passes through the AV node to the ventricles, the ventricles contract, pumping blood out to your body.
In atrial fibrillation, the upper chambers of your heart (atria) experience chaotic electrical signals. As a result, they quiver. The AV node — the electrical connection between the atria and the ventricles — is overloaded with impulses trying to get through to the ventricles. The ventricles also beat rapidly, but not as rapidly as the atria. The reason is that the AV node is like a highway on-ramp — only so many cars can get on at one time.
The result is a fast and irregular heart rhythm. The heart rate in atrial fibrillation may range from 100 to 175 beats a minute. The normal range for a heart rate is 60 to 100 beats a minute.
Underlying heart disease-including high blood pressure, heart valve disease, and coronary artery disease-is the most common cause of atrial fibrillation. Seen mostly in people older than 65, this type of atrial fibrillation is often the most complicated to manage.
At first, people usually have paroxysmal atrial fibrillation. Paroxysmal episodes go away on their own. They may last anywhere from a few seconds to a few weeks and may not cause symptoms.
Paroxysmal atrial fibrillation episodes may recur for weeks or years, although usually the disease progresses and atrial fibrillation becomes persistent, meaning that it no longer goes away on its own. Your doctor may try a procedure called cardioversion, using either medication or low-voltage electrical shock (electrical cardioversion), to return the irregular heartbeat to a normal rhythm (normal sinus rhythm). The decision to try cardioversion is based upon how bothersome you find the symptoms and how long the episode of atrial fibrillation has persisted.
There are some things you can do to try to prevent recurrent spells of atrial fibrillation. You may need to reduce or eliminate caffeinated and alcoholic beverages from your diet, because they can sometimes trigger an episode of atrial fibrillation. It's also important to be careful when taking over-the-counter (OTC) medications. Some, such as cold medicines containing pseudoephedrine, contain stimulants that can trigger atrial fibrillation. Also, some OTC medications can have dangerous interactions with anti-arrhythmic medications.
You may not be aware that your heart is not beating in a normal pattern, especially if it has been occurring for some time.
Symptoms may include:
Breathing difficulty while lying down.
Causes and Risk factors:
- Dizziness, light-headedness.
- Pulse that feels rapid, racing, pounding, fluttering, or too slow.
- Pulse that feels regular or irregular.
- Sensation of feeling the heart beat (palpitations).
- Sensation of tightness in the chest.
- Shortness of breath.
Arrhythmias are caused by a disruption of the normal electrical conduction system of the heart.
Normally, the four chambers of the heart (two atria and two ventricles) contract in a very specific, coordinated way. The electrical impulse that signals your heart to contract in a synchronized way begins in the sinoatrial node (SA node). This node is your heart's natural pacemaker.
The signal leaves the SA node and travels through the two upper chambers (atria). Then the signal passes through another node (the AV node), and finally, through the lower chambers (ventricles). This path enables the chambers to contract in a coordinated fashion.
In atrial fibrillation, the atria are stimulated to contract very quickly and differently from the normal pattern. The impulses are sent to the ventricles in an irregular pattern. Some impulses fail to be transmitted. This makes the ventricles beat abnormally, leading to an irregular (and usually fast) pulse.
In atrial flutter, the ventricles may beat very fast, but in a regular pattern.
If the atrial fibrillation/flutter is part of a condition called sick sinus syndrome, the sinus node may not work properly. The heart rate may alternate between slow and fast. As a result, there may not be enough blood to meet the needs of the body.
Atrial fibrillation can affect both men and women. It becomes more common with increasing age.
Causes of atrial fibrillation include:
Alcohol use (especially binge drinking).
- Congestive heart failure.
- Coronary artery disease (especially after a heart attack or coronary artery bypass surgery).
- High blood pressure (hypertension).
- Hypertrophic cardiomyopathy.
- Overactive thyroid gland (hyperthyroidism).
- Valvular heart disease (especially mitral stenosis and mitral regurgitation).
Risk factors for atrial fibrillation include:
: The older you are, the greater your risk of developing atrial fibrillation.
- HEART DISEASE: Anyone with heart disease, including valve problems, history of heart attack and heart surgery, has an increased risk of atrial fibrillation.
- HIGH BLOOD PRESSURE: Having high blood pressure, especially if it's not well controlled with lifestyle changes or medications can increase your risk of atrial fibrillation.
- OTHER CHRONIC CONDITIONS: People with thyroid problems, sleep apnea and other medical problems have an increased risk of atrial fibrillation.
- DRINKING ALCOHOL: For some people, drinking alcohol can trigger an episode of atrial fibrillation. Binge drinking — having five drinks in two hours for men, or four drinks for women — may put you at higher risk.
- FAMILY HISTORY: An increased risk of atrial fibrillation runs in some families.
The health care provider may hear a fast heartbeat while listening to the heart with a stethoscope. The pulse may feel rapid, irregular, or both. The normal heart rate is 60 - 100, but in atrial fibrillation/flutter the heart rate may be 100 - 175. Blood pressure may be normal or low.
An ECG shows atrial fibrillation or atrial flutter. Continuous ambulatory cardiac monitoring -- Holter monitor (24 hour test) -- may be necessary because the condition often occurs at some times but not others (sporadic).
To diagnose atrial fibrillation, your doctor may do tests that involve the following:
: In this noninvasive test, patches with wires (electrodes) are attached to your skin to measure electrical impulses given off by your heart. Impulses are recorded as waves displayed on a monitor or printed.
:This is a portable machine that records all of your heartbeats. You wear the monitor under your clothing. It records information about the electrical activity of your heart as you go about your normal activities for a day or two. You can press a button if you feel symptoms, so your doctor can know what heart rhythm was present at that moment.
:This device is similar to a Holter monitor except that not all of your heartbeats are recorded. There are two recorder types: One uses a phone to transmit signals from the recorder while you're experiencing symptoms. The other type is worn all the time (except while showering) for as long as a month. Event recorders are especially useful in diagnosing rhythm disturbances that occur at unpredictable times.
: In this noninvasive test, sound waves are used to produce a video image of your heart. Sound waves are directed at your heart from a wand-like device (transducer) that's held on your chest. The sound waves that bounce off your heart are reflected through your chest wall and processed electronically to provide video images of your heart in motion, to detect underlying structural heart disease.
: These help your doctor rule out thyroid problems or other substances in your blood that may lead to atrial fibrillation.
: X-ray images help your doctor see the condition of your lungs and heart. Your doctor can also use an X-ray to diagnose conditions other than atrial fibrillation that may explain your signs and symptoms.
Other tests include:
- Electrophysiologic study (EPS).
- Exercise treadmill ECG.
In certain cases, atrial fibrillation may need emergency treatment to get the heart back into normal rhythm. This treatment may involve electrical cardioversion or intravenous (IV) drugs such as dofetilide, amiodarone, or ibutilide. Drugs are typically needed to keep the pulse from being too fast.
Long-term treatment varies depending on the cause of the atrial fibrillation or flutter. Medications slow the heartbeat or the movement of the electrical impulse from the atria to the ventricles, and may include:
- Calcium channel blockers.
Anti-arrhythmic medications may be used to get the heart back into a normal rhythm. These medications may work well in many people, but they can have serious side effects.
Blood thinners, such as heparin, warfarin (Coumadin), or aspirin may help reduce the risk of a blood clot traveling in the body (such as a stroke). Your doctor will consider your age and other medical problems to decide which drug is best.
Some patients with atrial fibrillation, rapid heart rates, and intolerance to medication may need a catheter procedure on the atria called radiofrequency ablation.
For some patients with atrial flutter, radiofrequency ablation can cure the arrhythmia and is the treatment of choice. Some patients with atrial fibrillation and rapid heart rates may need the radiofrequency ablation done not on the atria, but directly on the AV junction (the area that normally filters the impulses coming from the atria before they proceed to the ventricles).
Ablation of the AV junction leads to complete heart block. Treatment for this condition requires a permanent pacemaker. The disorder is usually controllable with treatment. Many people with atrial fibrillation do very well. Atrial fibrillation tends to become a chronic condition, however. It may come back even with treatment.
Sometimes medications or cardioversion to control atrial fibrillation doesn't work. In those cases, your doctor may recommend a procedure to destroy the area of heart tissue that's causing the erratic electrical signals and restore your heart to a normal rhythm. These options can include:
Radiofrequency catheter ablation: In many people who have atrial fibrillation and an otherwise normal heart, atrial fibrillation is caused by rapidly discharging triggers, or "hot spots." These hot spots are like abnormal pacemaker cells that fire so rapidly that the upper chambers of your heart quiver instead of beating efficiently. Radiofrequency energy directed to these hot spots through a catheter inserted in an artery near your collarbone or leg may be used to destroy these hot spots, scarring the tissue so the erratic electrical signals are normalized. This corrects the arrhythmia without the need for medications or implantable devices. In some cases, other types of catheters that can freeze the heart tissue (cryotherapy) are used.
Surgical maze procedure: The maze procedure is often done during an open-heart surgery. Using a scalpel, doctors create several precise incisions in the upper chambers of your heart to create a pattern of scar tissue. Because scar tissue doesn't carry electricity, it interferes with stray electrical impulses that cause atrial fibrillation. Radiofrequency or cryotherapy can also be used to create the scars, and there are several variations of the surgical maze technique. The procedure has a high success rate, but because it usually requires open-heart surgery, it's generally reserved for people who don't respond to other treatments or when it can be done during other necessary heart surgery, such as coronary artery bypass surgery or heart valve repair. Some people need a pacemaker implanted after the procedure.
Medicine and medications:
Drugs such as digoxin, beta blockers (atenolol, metoprolol, propranolol), amiodarone, disopyramide, calcium antagonists (verapamil, diltiazem), sotalol, flecainide, procainamide, quinidine, propafenone, etc. Drugs (such as ibutilide) can sometimes restore the heart's normal rhythm. These drugs are given under medical supervision, and are delivered through an IV tube into a vein, usually in the patient's arm.
: The following drugs and medications are in some way related to, or used in the treatment. This service should be used as a supplement to, and NOT a substitute for, the expertise, skill, knowledge and judgment of healthcare practitioners.
DISCLAIMER: This information should not substitute for seeking responsible, professional medical care.