It also causes an increase in your heart rate. Sometimes no cause for the fibrillation can be found. Some people may have chest pain. When atrial fibrillation affects the pumping of your heart, your blood pressure may fall and you may feel lightheaded or faint. Occasionally, the first symptom is a stroke, caused by a blood clot that formed in the fibrillating atrium and traveled to the brain.
Some people have no symptoms.
Your health care provider will ask about your symptoms and examine you. An ECG measures the electrical activity of your heart. It will show a special pattern for atrial fibrillation. Your provider will use your medical history, physical exam, and blood tests to look for a treatable cause of the abnormal heartbeat. A helpful additional test is an echocardiogram.