Symptoms Caused by Atrial Fibrillation

Woman checking heart rate after sports
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The symptoms of atrial fibrillation can vary a lot from person to person, and even in the same person at different times. While atrial fibrillation itself is not a life-threatening arrhythmia, it can lead to complications—in particular, stroke—that can be disabling or fatal.

Some people with atrial fibrillation have no symptoms at all, and the arrhythmia is discovered only when a doctor or nurse takes their pulse or performs an electrocardiogram (ECG). This lack of symptoms, however, occurs only in a minority of people with this arrhythmia. In most cases, at least before it is adequately treated, atrial fibrillation is a great annoyance, if not downright distressing and intolerable.


The most common symptoms associated with atrial fibrillation are palpitations. “Palpitations” means an unusual and uncomfortable awareness of the heartbeat. In atrial fibrillation, palpitations are caused by the rapid, irregular heart rate that is commonly seen with this arrhythmia.

People who experience palpitations with atrial fibrillation usually complain of the sensation of a “fluttering” in the chest, often accompanied by a feeling of “skipped” beats, and occasionally by brief episodes of lightheadedness. Palpitations associated with atrial fibrillation might be only mildly irritating, or might be extremely disturbing, and their severity can wax and wane.

In some, the severity of the palpitations may depend on their emotional state, whether they’re sitting or lying down, their state of hydration, whether or not they’re sleep deprived, or several other factors related to daily life. Most of the time, however, no particular associations can be identified.

Palpitations are usually greatly diminished, and often eliminated, when the heart rate during atrial fibrillation is slowed with medications—a goal that can usually be accomplished quite readily.

Symptoms Caused by Loss of Effective Atrial Contractions

Also common with atrial fibrillation are reduced exercise tolerance, fatigue, dyspnea (shortness of breath), and even lightheadedness with almost any level of exertion. These symptoms are usually associated with the loss of cardiac efficiency that occurs when the atrial chambers are no longer able to beat effectively.

When atrial contraction is lost, the amount of blood the ventricles are able to eject with each heartbeat may become diminished. This limited cardiac output reduces a person’s exercise tolerance. Furthermore, when the atrial chambers stop beating effectively the blood tends to “back up” into the lungs, producing shortness of breath. In many people with atrial fibrillation cardiac efficiency may be perfectly adequate at rest, but during exertion, when the heart is pushed to work harder, symptoms may become quite severe.

Symptoms caused by the loss of effective atrial contractions tend to be much more troublesome in people who, in addition to atrial fibrillation, have cardiac conditions in which the ventricles are relatively “stiff.” Stiff ventricles tend to be highly dependent upon a strong atrial contraction in order to fill completely. When atrial contractions are lost in these patients, cardiac efficiency may drop very significantly.

Conditions that tend to produce stiff ventricles include hypertrophic cardiomyopathydiastolic dysfunctionaortic stenosis, and even chronic hypertension. In people with these conditions the onset of atrial fibrillation commonly produces symptoms that are particularly severe.

Angina: In people who have coronary artery disease, the rapid heart rate seen with atrial fibrillation can cause angina (chest discomfort).

Heart failure: In patients with heart failure, the additional reduction in cardiac efficiency brought on by atrial fibrillation can greatly worsen symptoms—chiefly, shortness of breath, weakness, and swelling in the legs.

Rarely, atrial fibrillation can produce heart failure all by itself. Any arrhythmia that is capable of making the heart beat very rapidly for several weeks or months can cause the heart muscle to weaken, and can lead to heart failure. Fortunately, this condition (which is referred to as “tachycardia-induced heart failure”), is a relatively rare consequence of atrial fibrillation.


Syncope, or an episode of loss of consciousness, is not common in atrial fibrillation. When syncope does occur, it is a strong clue that the patient may also have underlying sinus node disease, or sick sinus syndrome (SSS).

SSS is a generalized disorder of the heart’s electrical system, manifested by a heart rate that is so slow (referred to as bradycardia) that it produces symptoms of lightheadedness and weakness.

Atrial fibrillation is common in patients with SSS. In a way, atrial fibrillation “protects” patients with SSS, because it generally results in a heart rate that is fast enough to avoid symptoms of bradycardia. However, if the atrial fibrillation comes and goes periodically (as it often does), when the arrhythmia suddenly stops there is often a very long delay before the sick sinus node picks up again. That long pause before a heartbeat occurs is what produces the syncope.

Treating SSS requires the use of a permanent pacemaker. In people who have both SSS and atrial fibrillation, it is usually best to insert the pacemaker before aggressive steps are taken to treat the atrial fibrillation (because this treatment often causes the heart rate to slow).

Syncope is very rare with atrial fibrillation unless SSS is also present.


A much less rare—and the most feared—consequence of atrial fibrillation is stroke.

The increased risk of stroke is the real reason that it is always important to carefully consider the optimal treatment for atrial fibrillation—even in cases where the atrial fibrillation is well-tolerated and seems to be causing no particular problems.

Some people will have repeated episodes of atrial fibrillation without any symptoms whatsoever, until they, at last, suffer a stroke. Only after the stroke occurs is it discovered that they are having atrial fibrillation.

Recent evidence suggests that such “subclinical” atrial fibrillation is more common than anyone had realized, and that unrecognized atrial fibrillation may be an important cause of “cryptogenic stroke”—that is, a stroke whose cause is not immediately apparent.

A Word From Verywell

If you have atrial fibrillation your doctor will be asking you about all these symptoms before recommending a specific treatment plan. Try to be as accurate and complete as you can when sharing your medical history with your doctor. Palpitations, easy fatiguability, shortness of breath, chest discomfort, or episodes of lightheadedness or passing out—these are symptoms that you should always relate to your doctor, as well as details on what led to these symptoms.

A complete account of what you're experiencing will help your doctor better diagnose your condition and pick a treatment plan that's right for you. The two goals in treating atrial fibrillation are to prevent stroke and to control symptoms so that you could live a normal life.

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Article Sources
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  • American College of Cardiology Foundation, American Heart Association, European Society of Cardiology, et al. Management of Patients with Atrial Fibrillation (Compilation of 2006 ACCF/AHA/ESC and 2011 ACCF/AHA/HRS Recommendations): a Report of the American College of Cardiology/American Heart Association Task Force on practice guidelines. Circulation 2013; 127:1916.