What is Atrial Fibrillation?
What is atrial fibrillation?

Atrial fibrillation is an irregular and often rapid heart rate that commonly causes poor blood flow to the body. During atrial fibrillation, the heart's two upper chambers (the atria) beat chaotically and irregularly — out of coordination with the two lower chambers (the ventricles) of the heart. Atrial fibrillation symptoms include heart palpitations, shortness of breath and weakness.

Episodes of atrial fibrillation can come and go, or you may have chronic atrial fibrillation. Although atrial fibrillation itself usually isn't life-threatening, it is a serious medical condition that sometimes requires emergency treatment. It can lead to complications. Treatments for atrial fibrillation may include medications and other interventions to try to alter the heart's electrical system.

Symptoms

A heart in atrial fibrillation does not beat efficiently. It may not be able to pump enough blood out to your body with each heartbeat.

Some people with atrial fibrillation have no symptoms and are unaware of their condition until it is discovered during a physical examination. Those who do have atrial fibrillation symptoms may experience:


Palpitations, which are sensations of a racing, uncomfortable, irregular heartbeat or a flopping in your chest

Decreased blood pressure

Weakness

Lightheadedness

Confusion

Shortness of breath

Chest pain


Atrial fibrillation may be:

Occasional. In this case it is called paroxysmal (par-ok-SIZ-mul) atrial fibrillation. You may have symptoms that come and go, lasting for a few minutes to hours and then stopping on their own.

Chronic. With chronic atrial fibrillation, your heart rhythm is always abnormal.

Causes

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 hearts 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.

Possible causes of atrial fibrillation

Abnormalities or damage to the hearts structure are the most common cause of atrial fibrillation. Possible causes of atrial fibrillation include:

High blood pressure
Heart attacks
Abnormal heart valves
Heart defects you're born with (congenital)
An overactive thyroid gland or other metabolic imbalance
Exposure to stimulants such as medications, caffeine or tobacco, or to alcohol
Sick sinus syndrome — improper functioning of the heart's natural pacemaker
Emphysema or other lung diseases
Previous heart surgery
Viral infections
Stress due to pneumonia, surgery or other illnesses
Sleep apnea

However, some people who have atrial fibrillation do not have any heart defects or damage, a condition called lone atrial fibrillation. In lone atrial fibrillation, the cause is often unclear, and serious complications are rare.

Atrial flutter

Atrial flutter is similar to atrial fibrillation, but the rhythm in your atria is more organized and less chaotic than the abnormal patterns common with atrial fibrillation. Sometimes you may have atrial flutter that develops into atrial fibrillation and vice versa. The symptoms, causes and risk factors of atrial flutter are similar to those of atrial fibrillation. For example, strokes are a concern in someone with atrial flutter. As with atrial fibrillation, atrial flutter is usually not life-threatening when it is properly treated.

Western Medicine Treatment

In some people, a specific event or an underlying condition, such as a thyroid disorder, may trigger atrial fibrillation. If the condition that triggered your atrial fibrillation can be treated, you might not have any more heart rhythm problems — or at least not for quite some time. If your symptoms are bothersome or if this is
your first episode of atrial fibrillation, your doctor may attempt to reset the rhythm.

The treatment option best for you will depend on how long you've had atrial fibrillation, how bothersome your symptoms are and the underlying cause of your atrial fibrillation. Generally, the goals of treating atrial fibrillation are to:

Reset the rhythm or control the rate
Prevent blood clots

The strategy you and your doctor choose depends on many factors, including whether you have other problems with your heart and if you are able to take medications that can control your heart rhythm. In some cases, you may need a more invasive treatment, such as surgery or medical procedures using catheters. Resetting your hearts rhythm

Ideally, to treat atrial fibrillation, the heart rate and rhythm are reset to normal. To correct your condition, doctors may be able to reset your heart to its regular rhythm (sinus rhythm) using a procedure called cardioversion, depending on the underlying cause of atrial fibrillation and how long you've had it. Cardioversion can be done in two ways:

Cardioversion with drugs. This form of cardioversion uses medications called anti-arrhythmics to help restore normal sinus rhythm. Depending on your heart condition, your doctor may recommend
trying intravenous or oral medications to return your heart to normal rhythm. This is often done in the hospital with continuous monitoring of your heart rate. If your heart rhythm returns to normal, your doctor often will prescribe the same anti-arrhythmic or a similar one to try to prevent more spells of atrial fibrillation.

Electrical cardioversion. In this brief procedure, an electrical shock is delivered to your heart through paddles or patches placed on your chest. The shock stops your hearts electrical activity
momentarily. When your heart begins again, the hope is that it resumes its normal rhythm. The procedure is performed with sedation, so you shouldn't feel the electric shock.


Heart rate control

Sometimes atrial fibrillation cannot be converted to a normal heart rhythm. Then the goal is to slow the heart rate to between 60 and 100 beats a minute (rate control). Heart rate control can be achieved two ways:

Medications. Doctors have prescribed the medication digoxin (Lanoxin). It can control heart rate at rest, but not as well during activity. Most people require additional or alternative medications, such as calcium channel blockers or beta blockers. Other blood pressure lowering medications, such as angiotensin-converting enzyme (ACE) inhibitors, also are sometimes used to lower blood pressure
and reduce the risk of atrial fibrillation complications.

Atrioventricular (AV) node ablation. If medications don't work, or you have side effects, AV node ablation may be another option. The procedure involves applying radiofrequency energy to the pathway connecting the upper and lower chambers of your heart (AV node) through a long, thin tube (catheter) to destroy this small area of tissue.

The procedure prevents the atria from sending electrical impulses to the ventricles. The atria continue to fibrillate, though, and anticoagulant medication is still required. A pacemaker is then implanted to establish a normal rhythm. After AV node ablation, you'll need to continue to take blood-thinning medications to reduce
the risk of stroke, because your heart rhythm is still atrial fibrillation.

Preventing blood clots

Most people who have atrial fibrillation or who are undergoing certain treatments for atrial fibrillation are at especially high risk of blood clots that can lead to stroke. The risk is even higher if other heart disease is present along with atrial fibrillation. Your doctor may prescribe blood-thinning medications anticoagulants)
such as:

Warfarin (Coumadin). If you are prescribed warfarin, carefully follow your doctors instructions on taking it. Warfarin is a powerful medication that can have dangerous side effects. You'll need to have regular blood tests to monitor warfarin's effects.

Dabigatran (Pradaxa). Another option for preventing blood clots is dabigatran. Dabigatran is as effective as warfarin at preventing blood clots that can lead to strokes, and does not require blood
tests to make sure you're getting the proper dose. Talk to your doctor about taking dabigatran as an alternative to warfarin if you're concerned about your risk of stroke.


You may need to take medications to prevent blood clots in addition to medications designed to treat your irregular heartbeat. Many people have spells of atrial fibrillation and don't even know it — so you may need lifelong anticoagulants even after your rhythm has been restored to normal.

Adopted from mayoclinic.com