Overview

Atrial fibrillation (A-fib) is an irregular and often very rapid heart rhythm (arrhythmia) that can lead to blood clots in the heart. A-fib increases the risk of stroke, heart failure and other heart-related complications.

During atrial fibrillation, the heart’s upper chambers (the atria) beat chaotically and irregularly — out of sync with the lower chambers (the ventricles) of the heart. For many people, A-fib may have no symptoms. However, A-fib may cause a fast, pounding heartbeat (palpitations), shortness of breath or weakness.

Episodes of atrial fibrillation may come and go, or they may be persistent. Although A-fib itself usually isn’t life-threatening, it’s a serious medical condition that requires proper treatment to prevent stroke.Treatment for atrial fibrillation may include medications, therapy to reset the heart rhythm and catheter procedures to block faulty heart signals.A person with atrial fibrillation may also have a related heart rhythm problem called atrial flutter. Although atrial flutter is a different arrhythmia, the treatment is quite similar to atrial fibrillation.

Symptoms

Some people with atrial fibrillation (A-fib) don’t notice any symptoms. Those who do have atrial fibrillation symptoms may have signs and symptoms such as:

Atrial fibrillation may be:

When to see a doctor

If you have any signs or symptoms of atrial fibrillation, make an appointment with your doctor.If you have chest pain, seek immediate medical help. Chest pain could mean that you’re having a heart attack.

Causes

To understand the causes of A-fib, it may be helpful to know how the heart typically beats.The typical heart has four chambers — two upper chambers (atria) and two lower chambers (ventricles). Within the upper right chamber of the heart (right atrium) is a group of cells called the sinus node. The sinus node is the heart’s natural pacemaker. It produces the signal that starts each heartbeat.In a regular heart rhythm:

In atrial fibrillation, the signals in the upper chambers of the heart are chaotic. As a result, the upper chambers shake (quiver). The AV node is then bombarded with signals trying to get through to the lower heart chambers (ventricles). This causes 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.

Causes of atrial fibrillation

Problems with the heart’s structure are the most common cause of atrial fibrillation. Possible causes of atrial fibrillation include:

Some people who have atrial fibrillation have no known heart problems or heart damage.

Risk factors

Things that can increase the risk of atrial fibrillation (A-fib) include:

Complications

Blood clots are a dangerous complication of atrial fibrillation that can lead to stroke.In atrial fibrillation, the chaotic heart rhythm can cause blood to collect in the heart’s upper chambers (atria) and form clots. If a blood clot in the left upper chamber (left atrium) breaks free from the heart area, it can travel to the brain and cause a stroke.The risk of stroke from atrial fibrillation increases as you grow older. Other health conditions also may increase your risk of a stroke due to A-fib, including:

Prevention

Healthy lifestyle choices can reduce the risk of heart disease and may prevent atrial fibrillation. Here are some basic heart-healthy tips: