To diagnose atrial fibrillation, your doctor may review your signs and symptoms, review your medical history, and conduct a physical examination. Your doctor may order several tests to diagnose your condition, including:
- Electrocardiogram (ECG). An ECG uses small sensors (electrodes) attached to your chest and arms to sense and record electrical signals as they travel through your heart. This test is a primary tool for diagnosing atrial fibrillation.
- Holter monitor. This portable ECG device is carried in your pocket or worn on a belt or shoulder strap. It records your heart's activity for 24 hours or longer, which provides your doctor with a prolonged look at your heart rhythms.
Event recorder. This portable ECG device is intended to monitor your heart activity over a few weeks to a few months. You activate it only when you experience symptoms of a fast heart rate.
When you feel symptoms, you push a button, and an ECG strip of the preceding few minutes and following few minutes is recorded. This permits your doctor to determine your heart rhythm at the time of your symptoms.
Echocardiogram. In this noninvasive test, sound waves are used to produce a video image of your heart. Sound waves are directed at your heart from a wand-like device (transducer) that's held on your chest (transthoracic echocardiogram). The sound waves that bounce off your heart are reflected through your chest wall and processed electronically to provide video images of your heart in motion, to detect underlying structural heart disease.
Doctors may conduct a type of echocardiogram in which they insert a flexible tube with a transducer attached and guide it down your throat into your esophagus (transesophageal echocardiography). In this test, sound waves are used to produce images of your heart, which may be seen more clearly with this type of echocardiogram. Doctors may use this test to detect blood clots that may have formed in your heart.
- Blood tests. These help your doctor rule out thyroid problems or other substances in your blood that may lead to atrial fibrillation.
- Stress test. Also called exercise testing, stress testing involves running tests on your heart while you're exercising.
- Chest X-ray. X-ray images help your doctor see the condition of your lungs and heart. Your doctor can also use an X-ray to diagnose conditions other than atrial fibrillation that may explain your signs and symptoms.