Disease: Atrial Fibrillation

What Is Atrial Fibrillation?

About 2.7 million Americans have afib, a type of heart disease.

Atrial fibrillation is a common form of heart disease, and the most common cause of irregular heart rhythms that start in the upper chambers of the heart, called the atria.

The term fibrillation refers to a fluttering, disorganized type of heartbeat, also known as heart flutter.

"Atrial fibrillation tops the list of abnormalities that can occur in the heart's normal rhythm," says Douglas C. Westveer, MD, chief of cardiovascular disease at Beaumont Hospital in Troy, Mich.

According to the American Heart Association, about 2.7 million Americans have atrial fibrillation, or afib.

"Even more alarming, the incidence of atrial fibrillation is increasing and may reach epidemic proportions as more baby boomers enter older age groups," notes Dr. Westveer.

Understanding Afib

Your heart has four chambers inside of it: a left and right ventricle, and a left and right atruim (plural: atria). 

Normally, an electrical signal from the sinus node in the right atrium starts the heartbeat. The electrical impulse then travels to the left atrium and down to the two ventricles, causing the heart muscles to contract. In most people, this sequence occurs about 60 to 100 times a minute, creating a regular heartbeat.

But in atrial fibrillation, electrical signals begin in other parts of the two atria (or in nearby veins), creating an irregular storm of electrical signals.

The heart rate can then be as rapid as 400 to 600 beats a minute, explains John Miller, MD, an electrophysiologist at Indiana University Health in Indianapolis.

These electrical impulses are all trying to cause the ventricles to beat, Dr. Miller explains. The heart's switching station, called the atrioventricular node, protects the ventricles from some of the extra impulses, but it can't stop them all, and the ventricles begin to beat and quiver wildly.

And because the ventricles aren't beating properly, blood isn't pumped out of the heart effectively, and it may collect inside the heart, where it can form blood clots.

Atrial Fibrillation Symptoms

There are two types of atrial fibrillation. "Some patients have 'paroxysmal' atrial fibrillation, a relapsing form of arrhythmia that often lasts for hours and may recur frequently over time. Others have a chronic type that continues for the remainder of their lives," says Westveer.

Symptoms of atrial fibrillation may include:

  • The sensation of heart flutter known as palpitations
  • Shortness of breath
  • Fatigue
  • Dizziness
  • Chest pain

Causes and Risk Factors for Atrial Fibrillation

Atrial fibrillation is associated with many different conditions including:

  • Heart disease
  • High blood pressure
  • Chronic lung disease
  • Overactive thyroid gland
  • A blood clot that lodges in the lungs

In about 10 percent of people with atrial fibrillation, an underlying cause is never identified.

The biggest risk factors for atrial fibrillation are age and underlying heart disease, such as coronary artery disease or heart valve disease. Risk increases after age 60.

By age 65, about 4 percent of people will have atrial fibrillation. Other risk factors include smoking, excessive caffeine, and stress.

Complications of Atrial Fibrillation

The two big complications from atrial fibrillation are blood clots and heart failure. Blood clots occur because blood that is not moving normally tends to clot.

"Blood clots may form inside the atria over time and are a leading cause of stroke," says Westveer. A stroke can occur when a blood clot leaves the heart and gets lodged in an artery inside the brain. About 15 percent of all strokes happen in people with atrial fibrillation.

Heart failure occurs because the heart is not beating effectively and gradually gets weaker and weaker. Heart failure symptoms such as fatigue, shortness of breath, and fluid retention can develop over time as atrial fibrillation makes the heart work harder and grow weaker.

Fortunately, there are many options to help prevent stroke and heart failure symptoms.

"Although the prevalence of atrial fibrillation continues to increase, new treatment strategies are opening a brighter outlook for its management. The treatment choices should be fully discussed with your doctor," says Westveer.

Symptoms of Atrial Fibrillation

Do you have afib? Sometimes it can be difficult to tell.

If you have atrial fibrillation, a type of irregular heartbeat, a doctor's care is critical.

Though in most cases this type of heart flutter is not immediately life-threatening, it poses some major health risks, including fatigue, pain, and an increased risk for stroke.

The problem is that many of the 2.7 million Americans who have atrial fibrillation (also known as afib) don't even know it.

There are challenges when it comes to recognizing atrial fibrillation and seeking out help. For one, irregular heartbeat symptoms can be difficult to discern.

"Some patients may feel a rapid heart rate and palpitations, but up to 30 percent of patients have no perception of the rhythm disorder," says Carmine Sorbera, MD, a cardiologist and electrophysiologist with ColumbiaDoctors Medical Group in Hawthorne, N.Y.

Varying Symptoms of Afib

If you're at risk for an irregular heartbeat, you want to be on alert for anything that feels out of the ordinary. Be sure to ask about anything you suspect during checkups with your doctor.

The trouble with catching symptoms of atrial fibrillation is that they can vary widely. "The frequency of events is highly variable from patient to patient," says Anne Dougherty, MD, a cardiac electrophysiologist and professor of internal medicine at the University of Texas Health Science Center at Houston.

"Initially, months or years may pass between events," says Dr. Dougherty. "The natural history of atrial fibrillation is such that episodes tend to grow progressively more frequent and longer in duration over time and eventually become sustained or 'permanent.' That progression may occur over decades in some individuals or over days in others."

When to See Your Doctor

Thomas F. Deering, MD, chief of the Piedmont Heart Institute Arrhythmia Center in Georgia, says that beyond the typical racing of the heart, people should generally look for the following heart flutter symptoms: weakness, dizziness, shortness of breath, or chest pain. Any of these are reasons to see your doctor.

"If you feel significant symptoms, seek immediate help, which often means that one will need to be hospitalized," says Dr. Deering. When atrial fibrillation symptoms are mild, you can often be seen in your physician's office to determine the next best course of action.

Based on your specific condition, your doctor can usually provide individual guidance on what to do and when to do it, he adds.

The bottom line is that feeling this way is never normal, and when your heart health is on the line, waiting to see if symptoms of atrial fibrillation just go away is not a good idea.

Anyone with atrial fibrillation symptoms needs to be under the care of a doctor, who will have the tools and techniques to correctly diagnose and monitor your health to prevent the potentially life-threatening complications of atrial fibrillation.

What Causes Atrial Fibrillation?

Millions of Americans have afib, but the cause of the condition isn't always clear.

About 2.7 million people in the United States have atrial fibrillation, a rapid and irregular heartbeat. It's the most common type of heart arrhythmia, but not everyone with atrial fibrillation is sure how they got it.

"There are many different causes of atrial fibrillation," says Marc Gillinov, MD, surgical director of the Center for Atrial Fibrillation at the Cleveland Clinic and author of the book Heart 411.

Some causes of atrial fibrillation, or afib, are medical conditions beyond one's control, while others are lifestyle-related risk factors.

Heart Conditions

Afib frequently occurs in people with an underlying heart condition. Almost any heart condition can increase the risk for an abnormal rhythm and damage the heart's structure.

Some of the most common heart conditions that can lead to afib include:

  • High blood pressure (hypertension): When your blood pressure — the force of blood in your arteries — is too high, the heart has to work harder than normal.
  • Heart valve disease: Sometimes the heart valves don't work properly, which then makes the heart have trouble pumping blood.
  • A congenital heart defect: This is a heart abnormality that a person is born with.
  • Heart attack: This occurs when blood flow is blocked, damaging the heart.
  • Heart surgery: Afib can develop right after heart surgery or as a later complication.

Other Medical Conditions

Some illnesses are associated with atrial fibrillation, including:

  • Sleep apnea: A condition that causes pauses in breathing during sleep
  • Diabetes: A disease that develops when there is too much glucose (or sugar) in your blood
  • Hyperthyroidism: A condition that occurs when the thyroid gland makes too much thyroid hormone
  • Emphysema: A chronic obstructive pulmonary disease (COPD) that damages the air sacks in the lungs and makes it hard to breathe

"The numbers of people with sleep apnea, diabetes, and high blood pressure are increasing and contributing to more cases of afib," says Dr. Gillinov.

Uncontrollable Risk Factors

Be aware of these factors to help assess your afib risk:

  • Age: The single biggest risk factor for afib is age. "The exact reason is not known, but it may be due to progressive scarring of atrial tissue," says Gillinov. The odds of developing atrial fibrillation increase after the age of 60, and one in 10 people older than 80 have afib.
  • Family history: People with an immediate family member — a parent or a sibling — with atrial fibrillation are also at risk.

Controllable Risk Factors

It only makes sense to decrease your atrial fibrillation risk by modifying certain lifestyle habits:

  • Excessive alcohol use: Alcohol, and binge drinking in particular, can trigger atrial fibrillation.
  • Obesity: Being extremely overweight increases your risk for afib.

Atrial Fibrillation Prevention

Though in some cases the cause of atrial fibrillation is never found, if you have any of the medical conditions associated with afib, it's important to work with your doctor to get them under control. Get regular checkups and take medications as directed.

"If you have any of the risk factors, do very much the same things you would do to minimize high blood pressure," says Noel Boyle MD, PhD, director of the electrophysiology lab at UCLA's Cardiac Arrhythmia Center. "Follow a healthful diet and maintain a healthy weight. Exercise regularly, quit smoking, and reduce or eliminate alcohol."

If you are diagnosed with afib, there are ways to control it and prevent stroke, the most serious health threat with atrial fibrillation.

"Taking your pulse is the first step toward prevention, and it is very easy to learn," says Dr. Boyle. Place two fingers on the center of your neck; move them slightly to the left to your carotid artery. Press lightly until you feel a pulse. Alternatively, place two fingers just below where your wrist and thumb meet.

A normal pulse rate is 60 to 100 beats a minute and is strong and regular. "Don't be concerned by a skipped beat," says Boyle, "but if it feels irregular or fast, or if you have shortness of breath or chest pains, see your doctor."

And if you've been diagnosed with afib, ask your doctor how often you should check your pulse. Once a month may be enough.

Atrial Fibrillation Treatment

Drugs, medical procedures, or a combination of the two can help you manage the symptoms and risks of afib.

If you've been diagnosed with atrial fibrillation, you have many treatment options available to help control your condition.

Your doctor will help you decide on the best treatment for you. That choice is based on how often you have symptoms, what your heart rate is, and whether you have afib all the time or shorter episodes, called paroxysmal atrial fibrillation.

Other considerations may include how you respond to medications and other risk factors you have. Most people who have persistent or recurrent atrial fibrillation symptoms do need treatment.

"Atrial fibrillation treatment may include controlling symptoms, preventing stroke, and achieving long-term control of the disease," says David Wilber, MD, professor and director of the Cardiovascular Institute at Loyola University's Stritch School of Medicine in Chicago.

Electrical Cardioversion and Medical Cardioversion

If your heart is in fibrillation, you may need an emergency procedure to flip your heart back into a normal rhythm. "Cardioversion is used to get the heart beating in a normal rhythm, but it does not cure atrial fibrillation or decrease episodes of atrial fibrillation," explains Dr. Wilber.

  • Electrical cardioversion: An electric shock may be used to reset your heart rhythm. This procedure is done at the hospital while you are asleep under anesthesia for a short time. Cardioversion frequently restores a normal rhythm, but it may not last. You’ll need medications afterward to keep your heart rhythm under control.
  • Medical cardioversion: Drugs such as amiodarone (Cordarone) and dofetilide (Tikosyn) can also be used to get your heart out of fibrillation. These drugs are given intravenously in the hospital while you are closely monitored.

Anti-Arrhythmics and Other Medications

Once your heart is in normal rhythm, you may be given two types of drugs to help control atrial fibrillation.

"Medications to control symptoms are usually the first-line therapy in atrial fibrillation treatment," Wilber says, but he adds that "these medications can have side effects and they are less than 50 percent effective in controlling symptoms of paroxysmal atrial fibrillation."

  • Anti-arrhythmics: These drugs — such as sotalol (Betapace), amiodarone (Cordarone), flecainide (Tambocor), propafenone (Rythmol), or procainamide (Pronestyl) — help your heart return to a normal rhythm. You may need to stay in the hospital and be monitored when you start taking an anti-arrhythmic. These drugs work about 30 to 60 percent of the time, but they may lose their effect over time.
  • Rate control drugs: These drugs slow down your heart rate and help your heart pump more effectively, but they do not prevent abnormal heart rhythms. Examples of this type of medication include digoxin (Lanoxin), beta-blocker drugs, and calcium channel blockers.

Catheter Ablation and Other Procedures

If you don't respond well to anti-arrhythmics or rate control drugs, you may be a candidate for catheter ablation.

"Ablation is very effective and can result in long-term relief of atrial fibrillation," Wilber says. "Studies of people who have had this treatment show that after three to five years, about 70 to 90 percent are still free of atrial fibrillation."

  • Pulmonary vein ablation. The area where the pulmonary veins enter the left atrium in the upper part of the heart is where atrial fibrillation usually begins. By threading a long flexible tube, or catheter, into the left atrium, doctors can treat this area with radiofrequency energy to create scar tissue that blocks atrial fibrillation. Some newer types of catheter ablation use freezing instead of radiofrequency.
  • Ablation of the AV node. This procedure is also done through a catheter using radiofrequency energy, but it targets an area called the atrioventricular, or AV, node and permanently blocks electrical signals from traveling between the upper part of the heart and the lower part of the heart. After this procedure, you'll need a pacemaker to control your heartbeat. Because pulmonary vein ablation has a high success rate, AV node ablation is rarely used today.
  • Maze surgery. In this procedure, the surgeon makes small, precise cuts in the left and right atria to interrupt the irregular electrical pathways. The procedure often requires open heart surgery, so it is sometimes done along with other necessary open heart procedures, such as valve replacement. It can also be done via a less invasive "keyhole surgery" method.

Preventing Blood Clots and Stroke

Blood clots that form in the upper chambers of the heart during fibrillation can travel to the brain and cause a stroke.

"The risk of stroke in atrial fibrillation is about 5 percent per year," notes Wilber. To prevent this complication, your doctor may prescribe you medications to keep your blood from forming clots.

To measure your risk for having a stroke, your doctor may use a scoring system called the CHADS2 score. In this system, you are assigned points for each of your stroke risks. For example, you get one point if you have atrial fibrillation plus high blood pressure. You get another point if you are 75 or older. And if you've had a stroke in the past, you get 2 points.

The CHADS2 system is gradually being phased out in favor of a newer, more sophisticated scoring system known as CHA2DS2-VASc. Research has found that CHA2DS2-VASc is as good or better than CHADS2 at determining stroke risk among people diagnosed with afib. 

Regardless of which scoring system is used, your doctor may recommend one of the following treatments to reduce your risk of stroke:

  • Aspirin: If your score is zero or one, you may only be given aspirin as a blood thinner.
  • Warfarin (Coumadin): If your score is one or higher, you may be given the blood thinner warfarin. With this drug, you will need to have your blood tested regularly to make sure the drug level is right.
  • Dabigatran (Pradaxa): If your score is higher than two, your doctor may prescribe dabigatran, a newer type of blood thinner, or warfarin.
  • Apixaban (Eliquis) or rivaroxaban (Xarelto): These anticoagulants may be prescribed to reduce the risk of stroke in people diagnosed with afib. 

There are many options for atrial fibrillation treatment, and one or more of these treatments is probably right for you.

The best way to manage atrial fibrillation is to learn as much as you can about it and work closely with your doctor to come up with a plan to keep your symptoms under control and reduce the risk of complications.

Complications of Atrial Fibrillation

If not managed properly, afib can lead to life-threatening health problems.

Atrial fibrillation, or afib, is a problem with the heart's electrical system that causes a rapid and irregular heartbeat, known as an arrhythmia.

Although atrial fibrillation itself is not life-threatening, complications of the condition can be.

A major risk for people with afib is stroke, and more than 70 percent of people with afib who have a stroke will die because of a stroke, according to the National Stroke Association.

Treating Afib

Some people don't feel any atrial fibrillation symptoms at all. In others, this out-of-sync rhythm can cause problems including:

  • The feeling that your heart is racing, skipping a beat, or the sensation of "butterflies" (palpitations) in your chest
  • Shortness of breath, dizziness, and tiredness
  • Chest pain

Medications, including beta blockers and calcium channel blockers, can slow heart rate, relieving some of the problems with afib. Doctors can also prescribe antiarrhythmic medications to restore normal rhythm.

Drug side effects can be serious, but generally the risk is low, says Walid Saliba, MD, director of the electrophysiology lab and a staff cardiologist at the Cleveland Clinic in Ohio. You may be hospitalized when you first start taking antiarrhythmics so you can be carefully monitored.

Atrial fibrillation is a recurrent problem, and the goal when treating afib is to keep episodes as widely spaced as possible, says Dr. Saliba. When medications can't do the job, your medical team will suggest other approaches to manage afib.

Stroke and Atrial Fibrillation

With afib, your atria are quivering instead of beating regularly and don't have the power to move all blood into the ventricles. As a result, blood can pool in the atria, allowing clots to form.

If a clot leaves the heart, it can travel to the brain, causing a stroke. Your risk for stroke is greater if you have one or more of these risk factors for stroke:

  • Congestive heart failure
  • High blood pressure
  • Age older than 75 years
  • Diabetes
  • Prior stroke

Gender also factors in: Even though more men than women are diagnosed with atrial fibrillation, more women have strokes, explains John Miller, MD, an electrophysiologist at Indiana University Health in Indianapolis.

If you have risk factors for stroke, your doctor may put you on a blood-thinning medication. Coumadin (warfarin) has been shown to lower the risk of stroke by 80 percent, says Saliba.

However, blood thinners can cause bleeding, especially if you already have bleeding problems. As a result, people taking Coumadin must be closely monitored with regular blood tests to make sure the dose is just enough to prevent clots but not so much that it can cause bleeding.

Saliba says that newer drugs like Pradaxa (dabigatran) and Xarelto (rivaroxaban) have shown to be as effective as Coumadin at preventing stroke and do not require the monitoring.

Be sure to tell your doctor about other medications you take and to ask about whether blood thinners are safe for you. If they're not, there are procedures that could reduce your risk for stroke and may make long-term use of blood thinners unnecessary.

Other Complications of Afib

Heart failure is another risk for people with atrial fibrillation, especially if the afib goes untreated for a long time. Afib can weaken the heart, impairing its ability to circulate blood efficiently.

Research has also found a possible link between atrial fibrillation and dementia. A recent study out of Intermountain Medical Center in Murray, Utah, linked the development of dementia with atrial fibrillation.

Researchers there studied 37,000 people who took part in a heart study and found those with afib were 44 percent more likely to develop dementia than those without the condition, and that people younger than 70 with afib were 130 percent more likely to develop Alzheimer's disease.

But Dr. Miller says the study does not indicate that atrial fibrillation causes dementia, it only shows an association. He has another possible explanation for such a finding: People with afib may have subclinical strokes that they may not even be aware of. This type of stroke can cause brain damage that looks like Alzheimer's disease.

Avoiding Afib Complications

Talk with your doctor about your stroke risk factors and how to lessen them, says Miller. This should include lifestyle habits that can help you beat the odds of having a stroke and keep your heart in rhythm:

  • Maintain a healthy weight and get regular exercise — ask your doctor about how much activity is right for you.
  • Take any needed steps to manage high blood pressure and cholesterol.
  • Eat a heart-healthy diet.
  • Limit alcohol and caffeine if these trigger afib symptoms in you.
  • Don't smoke.
  • Keep taking your afib medications, even when you're feeling good.

Miller says you shouldn't need to limit your activity because you have afib. With the proper treatment, he says, atrial fibrillation "should be as invisible as possible."

Atrial Fibrillation News

Source: http://www.everydayhealth.com

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