Atrial Fibrillation Diagnosis

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Sometimes people have atrial fibrillation (AF), but don't have symptoms. For these people, AF is often found during a physical exam or EKG (electrocardiogram) test done for another purpose. Other times, AF is diagnosed after a person goes to the doctor because of symptoms.

To understand why a person has AF and the best way to treat it, the doctor will want to discover any immediate or underlying causes. Doctors use several methods to diagnose AF, including family and medical history, a physical exam, and several diagnostic tests and procedures.

Specialists Involved

A primary care doctor often is involved in the initial diagnosis and treatment of AF. These doctors can include:

Family practitioners
Internists

Doctors who specialize in the diagnosis and treatment of heart disease also may be involved, such as:

Cardiologists (doctors who take care of adults with heart problems)
Electrophysiologists; cardiologists who specialize in arrhythmias)

Family and Medical History

The doctor will ask questions about:

Symptoms. What symptoms are you having? Have you had palpitations (a feeling of a strong or fast heartbeat)? Are you dizzy or short of breath? Are your feet or ankles swollen (a possible sign of heart failure)? Do you have any chest pain?
Medical history. This includes other health problems, such as a history of heart disease, high blood pressure, lung disease, diabetes, or thyroid problems.
Family medical history. Does anyone in your family have a history of AF? Has anyone in your family ever had heart disease or high blood pressure? Has anyone had thyroid problems? Are there other illnesses or health problems in your family?
Health habits. These include smoking and alcohol or caffeine use.

Physical Exam

The doctor will do a complete cardiac exam, listening to the rate and rhythm of your heartbeat and taking your pulse and blood pressure reading. The doctor will likely check to see whether you have any sign of problems with your heart muscle or valves. He or she will listen to your lungs to check for signs of heart failure.

The doctor also will check for swelling in the legs or feet and look for an enlarged thyroid gland or other signs of hyperthyroidism.

Diagnostic Tests and Procedures

EKG

An EKG is a simple test that detects and records the electrical activity of your heart. It is the most useful test for diagnosing AF. It shows how fast the heart is beating and its rhythm (steady or irregular). It also records the timing of the electrical signals as they pass through each part of the heart.

A standard EKG test only records the heartbeat for a few seconds. It won't detect an AF episode that doesn't happen during the test. To diagnose paroxysmal AF, the doctor may ask you to wear a portable EKG monitor that can record your heartbeat for longer periods. The two most common types of portable EKGs are Holter and event monitors.

Holter Monitor

Also called an ambulatory EKG, this device records the electrical signals of the heart for a full 24- or 48-hour period. You wear small patches called electrodes on your chest that are connected by wires to a small, portable recorder. The recorder can be clipped to a belt, kept in a pocket, or hung around your neck.

During the time you're wearing a Holter monitor, you do your usual daily activities and keep a notebook, noting any symptoms you have and the time they occurred. You then return both the recorder and the notebook to the doctor to read the results. The doctor can see how your heart was beating at the time you had symptoms.

Event Monitor

Event monitors are useful to diagnose AF that occurs only once in a while. The device is worn continuously, but only records the heart's electrical activity when you push a button. You push the button on the device when you feel symptoms. Event monitors can be worn for 1 to 2 months, or as long as it takes to get a recording of the heart when symptoms are occurring.

Other Tests Used to Diagnose Atrial Fibrillation

Echocardiogram

This test uses sound waves to create a moving picture of your heart. An echocardiogram provides information about the size and shape of your heart and how well your heart chambers and valves are functioning. The test also can identify areas of poor blood flow to the heart, areas of heart muscle that aren't contracting normally, and previous injury to the heart muscle caused by poor blood flow.

This test is sometimes called a transthoracic echocardiogram. It's noninvasive and is done by placing an echo "probe" on your chest wall. The procedure is the same technique used for obtaining sonograms in pregnant women.

Transesophageal Echocardiogram

A transesophageal echocardiogram, or TEE, takes pictures of the heart through your esophagus (the tube leading from your mouth to your stomach). The atria are deep in the chest and often can't be seen very well on a regular echocardiogram. A doctor can see the atria much better with a TEE. In this test, the transducer is attached to the end of a flexible tube that's guided down your throat and into your esophagus. TEE is usually done while the patient under some sedation. TEE is used to detect clots that may be developing in the atria because of AF.

Blood Tests

These tests check the level of thyroid hormone and the balance of your body's electrolytes. Electrolytes are minerals in your blood and body fluids that are essential for normal health and functioning of your body's cells and organs