What Is Atrial Fibrillation?

Atrial fibrillation can cause worrisome symptoms — or none you notice. But treatment for this heart rhythm problem is important to lower your risk of stroke.

To understand what atrial fibrillation is, you need to know what an arrhythmia is. Simply put, an arrhythmia means your heart rhythm is out of sync — beating too fast, too slow, or irregularly.

Not all arrhythmias are serious or impact your health or longevity, and benign arrhythmias don’t need any treatment. For example, almost everyone has felt their heart race or skip a beat if they are scared or sleep deprived or perhaps had one cup of coffee too many. But your heart skipping a beat doesn’t indicate a serious heart rhythm problem.

Some kinds of arrhythmias do need medical attention because the arrhythmia either poses an immediate danger or is associated with other health problems. Atrial fibrillation is the most common kind of heart arrhythmia that usually needs treatment.

The condition affects almost three million Americans, according to the Centers for Disease Control and Prevention (CDC). Although not directly life-threatening, atrial fibrillation (also called Afib or AF) raises your risk for potentially serious complications, especially blood clots that can cause strokes.

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What causes the irregular heartbeat of Afib

If you wonder what atrial fibrillation is caused by, the answer centers around a glitch in your heart’s electrical system.

AF occurs when the electrical activity in the top chambers of your heart (the atria) become disorganized. This replaces the organized electrical activity generated by your heart’s sinus node — specialized cells in the upper right chamber of your heart that normally create steady electrical impulses to control your heartbeat. The resulting disordered electrical activity causes your heart to beat irregularly.

Although some people don’t feel any Afib symptoms (and may not even be aware they have the condition until it’s found during a physical), others may feel unusually tired, and many people with the arrhythmia feel their heart seeming to flutter and skip beats. Symptoms can also include shortness of breath, chest pain, feeling lightheaded or dizzy, or even fainting

The exact cause of atrial fibrillation isn’t always easy to pinpoint. Afib, however, is often linked to abnormalities or damage to the heart's structure from heart disease, heart valve problems, heart surgery, or congenital heart disease. High blood pressure accounts for about one in five cases of Afib, according to the CDC.

An overactive thyroid gland, lung disease, sleep apnea, diabetes, kidney disease, and certain viral illnesses and stimulant drugs are also potential triggers for atrial fibrillation. Smoking, obesity, moderate-to-heavy alcohol use, and advancing age all increase the risk for Afib, too.

On the other hand, some people who experience Afib don't have any heart disease or damage or other possible explanations for the condition. In this case, when the cause is unclear, the arrhythmia is called lone atrial fibrillation, and it is rarely associated with any serious complications.

Diagnosing atrial fibrillation

Atrial fibrillation is diagnosed based on your medical and family history, a physical exam, the results from an electrocardiogram (ECG), and possibly other tests. For example, if your symptoms suggest Afib but you are not currently experiencing the arrhythmia, you may wear a monitor, or a smartwatch equipped with ECG technology, to record your heart rhythm over a period of time.

If you’re found to have atrial fibrillation, your doctor will check for any condition that might be causing the arrythmia and can be treated, like hyperthyroidism, for example. Your risk for developing dangerous blood clots and the type of Afib you have will be assessed to decide on the right plan of action for you.

There are four main types of atrial fibrillation, the National Heart, Lung and Blood Institute (NHLBI) explains.

• Paroxysmal Afib describes a brief episode of atrial fibrillation that may have strong symptoms, or none at all; it usually stops in less than 24 hours but can last up to a week. You may not need treatment if symptoms go away and the arrhythmia doesn’t recur often.
• Persistent atrial fibrillation means the abnormal heart rhythm lasts for more than a week. While it sometimes stops on its own, the arrhythmia will likely need treatment, according to the NHLBI.
• Long term persistent Afib means the abnormal heart rhythm lasts for more than a year.
• When atrial fibrillation does not improve, even after procedures and medications given to restore a normal heart rhythm, your atrial fibrillation is considered permanent.

Treating Afib is important

Because atrial fibrillation disrupts the normal pumping action of the heart, it can lead to the formation of blood clots. If a clot breaks off, enters the bloodstream, and clogs an artery leading to the brain, a stroke results.

Around 20 percent of people who experience strokes have Afib, the American Heart Association points out. Because the arrhythmia is a strong risk factor for stroke, patients with the condition are usually placed on blood thinners.

Treating atrial fibrillation involves more than just preventing blood clots, however. Medications, including beta blockers and calcium channel blockers, can help restore a normal rhythm or reduce an overly high heart rate.

Healthy lifestyle changes, including weight control and regular exercise, stopping smoking, and cutting back on alcohol use, can also help improve symptoms.

But if Afib remains an ongoing problem, your doctor may recommend a procedure to help including:

• Electrical cardioversion. If an episode of Afib is ongoing and causing worrisome symptoms, and medication hasn’t helped, this procedure uses low-energy shocks to the heart to restore normal heart rhythm. It may be carried out in an emergency room.
• Catheter ablation. When heart-healthy changes and medication don’t improve symptoms over time, you may be a candidate for this minimally invasive procedure, which destroys the heart tissue causing the arrhythmia.
• Pacemaker. Some atrial fibrillation is triggered by a slow heartbeat, often caused by a condition called sick sinus syndrome. A pacemaker for that condition can also treat Afib by keeping the heart rate from going too low.

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