Your doctor will ask about your symptoms and examine you. The diagnosis can be confirmed with an electrocardiogram (ECG). An ECG measures the electrical activity of your heart. It will show a special pattern when atrial fibrillation is occurring. Sometimes atrial fibrillation comes and goes before it can be seen on an ECG. In this case, you may have to wear a Holter monitor or event recorder to record your heart rate. The Holter monitor is a portable ECG used to detect heart rhythm problems.

Your doctor will use your medical history, physical exam, and blood tests to look for a treatable cause of the abnormal heartbeat. You may also have an echocardiogram. This test uses sound waves to make images of your heart. It is a way to check for problems with the structure of the heart, such as an abnormal mitral valve.

Treatment depends on the cause of the irregular heartbeat, the severity of your symptoms, and your medical history. If a medical problem is causing atrial fibrillation, treating the problem usually causes the rhythm to go back to normal.  If your symptoms are not severe, treatment is usually a medicine to keep your heart from beating too fast. Medicines that can keep the heart from beating too fast are beta blockers, digoxin, and the calcium channel blockers diltiazem and verapamil.

Atrial fibrillation can cause blood clots to form in the heart. Blood clots in the heart can break off and cause a stroke. If your medical history puts you at high risk for forming a blood clot, you may need to take blood thinners, such as Coumadin, to prevent a stroke.

If your symptoms are more severe, you may be better off having your heart back in a normal rhythm. To get your heart back in a normal rhythm, you may be treated with anti-arrhythmic medicines.  If medicines don't work, your doctor might suggest a procedure that uses electrical energy delivered to the inside of the heart to treat abnormal heart rhythms. It blocks abnormal electrical impulses in the heart and helps stop abnormal heart rhythms.