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Questions about Symptoms

To diagnose AF, your doctor will ask you a number of questions. He or she will ask you to describe:

  •  Your symptoms
  • How often you experience them
  • How severe they are and what, if anything, seems to make them better or worse

Medical History

Your doctor will ask about your medical history, particularly any history of:

  • Heart ailments
  • Your family history
  • Your health habits, particularly smoking, alcohol and caffeine use

Complete Cardiac Exam

Your doctor also will perform a complete cardiac exam:

  • Listen to the rate and rhythm of your heartbeat
  • Take your pulse and blood pressure reading
  • Check to see whether you have any sign of problems with your heart muscle or valves
  • Listen to your lungs for signs of heart failure
  • Check for swelling in the legs or feet and look for an enlarged thyroid gland or other signs of hyperthyroidism

Diagnostic Tests

To definitively diagnose AF, however, your doctor may order one or more of the following tests:

Electrocardiogram (ECG)

ECG/EKG WavesPainless, Noninvasive Test Using Electrodes

This is a painless, noninvasive test in which patches with electrodes are attached to your skin to measure electrical impulses produced by your heart. These impulses are recorded as waves displayed on a monitor or printed out on graph paper.

Most Useful Test for Diagnosing AF

This test is the most useful for diagnosing AF. It shows how fast your heart is beating and its rhythm (steady or irregular).

Only Records Heartbeat for a Few Seconds

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, however. It will not detect an AF episode that doesn't happen during the test.

To diagnose paroxysmal or chronic AF, your 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

Records Heartbeats for 24 or 48 Hours

This is a portable device that records all of your heartbeats over an extended period, usually either 24 or 48 hours.

  • You wear small patches with 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.
  • You can press a button if you are experiencing symptoms, so your doctor will know what your heart rhythm was at the time of the symptoms.

Event Monitor

Used to Diagnose AF That Occurs Occasionally

This machine is similar to the Holter monitor, except that not all of your heartbeats are recorded. It is used to diagnose AF that occurs only occasionally.

  • You wear the device continuously, but it only records electrical activity when you push a button -- and you only push the button when you feel symptoms.
  • These devices may be worn for as long as one to two months.


Noninvasive Test

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.
  • Identifies 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.
  • Noninvasive and is performed by placing a probe on your chest wall. It is the same technique used in sonograms in pregnant women.

Blood Tests

These tests are used to detect:

  • Level of thyroid hormones
  • Balance of your body's electrolytes, minerals in your blood and body fluids that are essential for normal health and functioning of your body's cells and organs

Abnormal levels of these substances may lead to atrial fibrillation.

Contact Information

Cardiac Surgery
Division of the CardioVascular Institute
Beth Israel Deaconess Medical Center
Lowry Medical Office Building, 2A
110 Francis Street
Boston, MA 02215
Phone: 617-632-8383