Atrial fibrillation, commonly known as AFib, is a heart condition characterized by a quivering or irregular heartbeat, called arrhythmia, says the American Heart Association. Millions of people across the globe currently live with AFib.

When a person has AFib, the heart’s two upper chambers, known as the atria, beat chaotically and do not coordinate with the two lower chambers, states the Mayo Clinic. AFib can cause heart palpitations, shortness of breath and weakness. AFib is not often life-threatening, and symptoms may come and go. However, side effects of the condition can be dangerous.

AFib often results in poor blood flow, which can cause pooling of blood in the atria. The AHA notes that the risks of clotting increase as blood pool. If a clots forms in the atria, it can be pumped out of the heart and reach the brain, potentially blocking off the blood supply to an artery in the brain. This is known as an embolic stroke.

AFib also can reduce the heart’s pumping capacity. An otherwise healthy heart may be able to compensate for this reduction in efficiency. But those with damaged heart muscle or valves cannot. AFib can trigger breathlessness and exercise intolerance and potentially coronary artery disease, offers Harvard Medical School. Other problems from poor pumping can cause blood to back up into the pulmonary veins, the vessels that return oxygen-rich blood from the lungs to the heart. This can cause fluid in the lungs. Fluid also can build up in the feet, ankles and legs.

There are various potential causes for AFib, including the following conditions:

• high blood pressure

• abnormal heart valves

• previous heart attack

• congenital heart defects

• overactive thyroid

• exposure to stimulants

• previous heart surgery

• lung disease

Some people with AFib do not have any heart defects or damage, and the cause is unclear.

The Mayo Clinic says treatment goals for AFib include resetting the rhythm or controlling the rate of the atrial valves, known as cardioversion. This can be done electrically or through the use of drugs. Sometimes, other therapies to control atrial fibrillation do not work. In these cases, a doctor may recommend a procedure to destroy the area of heart tissue that’s causing the erratic electrical signals and restore the heart to a normal rhythm. Medication to prevent blood clots and reduce the risk for stroke often are prescribed.

Atrial fibrillation can be scary, but it’s manageable and the life-threatening side effects that may accompany it oftentimes can be mitigated.