The symptoms of AF are varying based upon how fast the ventricles are beating and the presence or absence of underlying heart disease.

If the ventricles beat more rapidly or irregularly, symptoms may be more severe and include:

• Difficulty breathing

• Shortness of breath with exertion

• Fainting, or near fainting, due to a reduction in blood flow to the brain

• Confusion, due to a reduction in blood supply to the brain

• Chest discomfort

• Fatigue

If the person has underlying heart disease, more serious symptoms of heart failure can develop:

• Angina or even a heart attack, primarily in people with underlying coronary disease

• Shortness of breath at rest or at night

• Swelling of the legs

• Rapid weight gain due to fluid accumulation