Atrial fibrillation (also known as AF or AFib) is the most common type of arrhythmia (irregular heartbeat or heart rhythm). The most common symptom of AF is heart palpitations (an irregular and rapid heartbeat, typically experienced as a rapid thumping in the chest). The majority of people with AF live active, healthy lives with treatment. However, AF can have serious complications, especially if it is not properly managed or treated.

AF increases your risk for stroke. In AF, the electrical signals in the atria (upper chambers of the heart) are so fast and disorganized that they cannot pump blood effectively into the ventricles (lower chambers of the heart). As a result, blood pools in the heart (the atria chambers) and blood clots can form in the atria. These clots can then travel to the brain or other parts of the body. A stroke occurs when a blood clot blocks blood from reaching the brain. Learn more about the heart and atrial fibrillation in "What is atrial fibrillation?"

Atrial fibrillation causes about 15% of all strokes. This number goes up to about 30% in people over 60 years old. Although the risk for stroke varies with each person, people with AF have 3 to 5 times as great a risk of stroke caused by a blood clot compared to people without AF.

A stroke damages the brain and causes a sudden loss of brain function. A stroke can affect your ability to see, remember, move, speak, reason, read, and write. Symptoms of stroke include sudden weakness or numbness in the face, arm, or leg, sudden difficult speaking or understanding, sudden severe and unusual headache, sudden dizziness or loss of balance, and sudden vision problems. If you experience any of these, seek immediate medical assistance or call 9-1-1.

If you have been diagnosed with atrial fibrillation, use our Atrial Fibrillation: Stroke Risk Assessment tool to find out your risk of stroke.

Because AF can sometimes cause long-term damage to the heart, heart failure is a serious complication of AF. An uncontrolled and irregular heart rate for long periods of time (weeks or months) can damage the heart muscle. The damaged heart cannot pump blood effectively to the rest of the body, resulting in heart failure.

AF also increases your risk of being hospitalized. One-third of men and one-half of women with AF end up going to the hospital because of AF symptoms. Hospital trips can be disruptive to your life and may cause significant physical and emotional distress to you and your family.

Despite these complications, AF can be effectively managed so that your risk of these complications is reduced. Learn more about how atrial fibrillation is treated in "How is atrial fibrillation treated?"