Over the course of a normal lifespan, the heart will beat 2 to 3 billion times, rhythmically contracting nonstop to pump blood throughout your body. When it’s working well, you might not give the heart much thought. But when something’s amiss, it can have serious implications for your health.

Heart problems often trigger a common set of symptoms: shortness of breath, feeling tired, difficulty performing everyday activities, and palpitations—which feel as if the heart is pounding in the chest. These symptoms can be caused by a number of cardiac conditions, one of which is called atrial fibrillation, or AFib.

AFib is the most common type of irregular heart rhythm (also called arrhythmia). It affects an estimated 2.7 to 6.1 million people in the U.S. at any given time, and causes about 450,000 hospitalizations each year.

AFib can affect people of any age, including children, though it mostly occurs in people over 60. As the population grows older, the number of cases is expected to rise; experts estimate there will be 12.1 million cases in the U.S. by 2030.

While AFib is a serious condition, various treatments, including lifestyle modification, medications, and medical procedures can help.

AFib is a cardiac arrhythmia that interferes with how effectively the heart pumps blood throughout the body.

In a healthy heart, its four chambers—two upper atria and two lower ventricles—work together, contracting and pumping blood at a carefully controlled pace and rhythm.

In atrial fibrillation, however, the two upper chambers twitch and quiver rapidly and with a disordered, irregular rhythm. As a result, the atria do not contract fully, preventing them from efficiently pumping blood into the ventricles. As a result, blood can pool in the atria, increasing the risk of blood clot formation and stroke. And because the upper and lower chambers of the heart do not contract in a coordinated pattern, the amount of blood pumped throughout the body is significantly reduced.

AFib often begins with short episodes of rapid, irregular heartbeats that go away on their own after a few days. But over time, the condition progresses, and these episodes become more frequent and longer lasting.

There are four main types of AFib, based on how long the condition lasts:

• Paroxysmal atrial fibrillation develops suddenly and resolves within 7 days of onset.
• Persistent atrial fibrillation is when AFib episodes last for over 7 days.
• Long-standing persistent atrial fibrillation is AFib that persists for 12 months or longer.
• Permanent atrial fibrillation describes AFib in which the heart’s rhythm remains irregular in spite of previous attempts to restore or maintain normal heart rhythm. At this stage, the doctor and patient jointly decide to stop trying to control heart rhythm and AFib is permanent. Treatment instead focuses on lowering heartrate in these patients.   

Several factors and medical conditions are known to cause or increase the risk for AFib, including:

• Increasing age
• High blood pressure
• Cardiovascular disease (heart failure, coronary artery disease, valvular heart disease, rheumatic heart disease, cardiomyopathy)
• Obstructive sleep apnea
• Obesity
• Diabetes
• Chronic kidney disease
• Excessive alcohol consumption, including binge drinking
• Cigarette smoking
• Hyperthyroidism
• Family history of AFib
• Male sex
• Previous heart surgery (in particular, risk is increased in the first few days following surgery)

AFib can cause a number of symptoms, including:

• Palpitations (sensation that heart is pounding, fluttering, skipping beats, or beating rapidly)
• Fatigue
• Shortness of breath
• Light-headedness
• Dizziness
• Weakness
• Rapid heartrate (100–160 or more beats per minute)
• Chest pain or discomfort
• Exercise intolerance (feeling excessively fatigued during exercise)
• Irregular pulse

Some people who have AFib do not have any symptoms.

To diagnose AFib, your doctor will assess your medical history, conduct a physical exam, and run one or more diagnostic tests.

To obtain a medical history, your doctor may ask about symptoms, when they began, and whether you have any risk factors for AFib.

During the physical exam, although your doctor will check your pulse to see if there is an irregular heartbeat, diagnosis almost always requires an electrocardiogram, also known as an ECG or EKG (a test that measures the heart’s electoral activity).

If you are diagnosed with AFib, your doctor may also order an echocardiogram, or ultrasound of the heart. This imaging study can detect structural irregularities in the heart. (It’s important to note that bloodwork is usually necessary to determine the exact cause of AFib.)

Treatments for AFib aim to prevent stroke, restore normal heartrate or heart rhythm, reduce symptoms and/or stop the condition from worsening.

• Stroke Prevention. Anticoagulants, commonly known as blood thinners, are often used to reduce risk of the formation of blood clots. This, in turn, lowers the risk of stroke.
• Restore normal heartrate. Beta blockers, calcium channel blockers, and digoxin can help slow the heartrate of people with AFib. If the above treatments don’t help or if patients are unable to take them, a catheter ablation may be necessary. In this procedure, a doctor inserts a catheter (a thin tube) into a vein or artery and maneuvers it through to the heart. Using the tip of the catheter, the doctor applies high-energy radiofrequency signals, a laser, or very cold temperatures to the AV (atrioventricular) node, a part of the heart involved sending electrical signals from the atria to the two lower chambers of the heart. The procedure destroys (or ablates) a small area of heart tissue. This disrupts the transmission of the abnormal electrical signals that caused the heart to beat too fast. People who undergo catheter ablation must have a pacemaker implanted to regulate their heartrate.
• Restore normal heart rhythm. Instead of restoring a patient’s normal heartrate, doctors may opt to re-establish a normal heart rhythm. This may be done using medications called anti-arrhythmic drugs, catheter ablation, surgical ablation, or a procedure called electrical cardioversion, in which an electrical shock is delivered to the heart through electrode patches or paddles that are placed on the chest—or the chest and back. The shock is delivered at a precise moment in the heart’s beating cycle.
• Lifestyle modifications. Many factors that cause or increase the risk of AFib can be reversed by lifestyle modification, including diet, exercise, and stress management. Doctors can advise patients about what lifestyle changes may help reduce symptoms and/or the progression of AFib. 

Though AFib is serious condition, millions of people in the U.S. live with it. Timely treatment, regular monitoring of the heart, and appropriate lifestyle changes can help people who have AFib manage symptoms and live longer, healthier lives.