Diagnosis of AFib

Reviewed by: HU Medical Review Board | Last reviewed: January 2024

Atrial fibrillation (AFib) is a heart rhythm disorder that feels like rapid or irregular heartbeats. It is the most common type of arrhythmia and can affect people of all ages and backgrounds.1-3

If left undiagnosed and untreated, AFib can lead to serious complications, like heart attack or stroke. If your doctor suspects you have AFib based on your symptoms, certain tests and evaluations can help confirm the diagnosis. Getting a timely and accurate AFib diagnosis can help save your life.1-3

How is atrial fibrillation diagnosed?

An AFib diagnosis starts with a visit to your doctor. They will do a thorough medical evaluation that includes:1-3

  • A physical exam – Your doctor will do a thorough exam to assess your overall health. For example, they will check for any swelling in your ankles, legs, or feet. They will also check your blood pressure, pulse, and height/weight, and they will listen to your lungs.
  • A complete medical history – Your doctor will ask you about your personal medical history, your family history of heart disease, and your eating and exercise habits. This helps give them a complete picture of your health and risk level for AFib.
  • Blood tests – Your doctor may order blood tests to check things like thyroid function and cholesterol levels.

From there, your doctor may refer you to a heart specialist (cardiologist) for more detailed tests and procedures.3

Types of diagnostic tests and procedures

Several tests and procedures can help diagnose AFib. These tests provide more detailed information on your heart health.1-3

Electrocardiogram (ECG or EKG)

This test records the electrical activity of your heart. It is often the first step in diagnosing AFib. Small sensors (electrodes) are attached to your chest, arms, and legs to create a visual of your heart's rhythm. It is a quick and painless test and can provide a lot of vital information on the health of your heart.1-3

Echocardiogram

This ultrasound test creates detailed images of your heart, including the valves and chambers, and how the heart is pumping. An echocardiogram helps identify any areas that are not performing as they should. It may also locate blood clots in the heart.1-3

Holter monitor

For people with symptoms that come and go, a Holter monitor may be helpful. This portable device records your heart's activity over 24 to 48 hours, providing a more extended snapshot of your heart rhythm.1-3

Event monitor

An event monitor is similar to a Holter monitor but used for longer periods. This monitor can be worn for weeks or even months. An event monitor can continuously record your heart rhythm for the duration that you wear it. With some monitors, you may be able to press a button to mark when you have AFib symptoms.1-3

Implantable loop recorder

This is a small device that continuously monitors the heart's electrical activity for an extended time (years). Some loop recorders can be worn outside the body. Some are implanted under the skin. The recorder stores data about irregular heart rhythms to help doctors make an accurate diagnosis. It can be helpful for people with intermittent AFib.2,3

Exercise stress test

An exercise stress test evaluates your heart while you exercise. This can help catch any abnormal or unusual heart activity.2

During a stress test, you are asked to exercise on a treadmill or stationary bike while connected to an ECG machine. While you exercise, the ECG monitors the electrical activity of your heart and captures any irregularities in the rhythm. If you have symptoms like heart palpitations, chest pain, or shortness of breath during the stress test, it may point to an AFib diagnosis.2

Other diagnostic tests for AFib may include:1-3

  • Chest X-ray
  • Sleep study to check for obstructive sleep apnea
  • Transesophageal echocardiography to check for blood clots in the heart’s upper chambers

Who performs these tests?

Several health professionals specialize in diagnostic tests for the heart. The following health professionals give and perform these tests:3,4

  • Cardiologists – Doctors with special training in heart health. They may order and interpret diagnostic tests, helping to create a complete picture of your heart's health. They treat heart diseases with medicine, surgeries, and noninvasive procedures.
  • Cardiac imaging specialists – Health professionals who specialize in advanced imaging techniques to look at the heart and its parts.
  • Electrophysiologists – Cardiologists with additional training in heart rhythm disorders (arrhythmias). They can also perform surgeries that a person with AFib might need.

Screening methods for AFib

Early detection of AFib is crucial to getting the right treatment. Routine screening is not standard practice for most people. However, if you have any of the known risk factors for AFib, these methods can help you stay on top of any symptoms that may arise:1-3,5

  • Pulse check – Check your pulse regularly. If you notice anything unusual, tell your doctor.
  • Blood pressure monitoring – High blood pressure causes 1 in 5 AFib cases. Get your blood pressure checked regularly. For adults with heart disease or who are over age 40, this should be done at least once a year. Ask your doctor how often you should have your blood pressure checked.
  • Mobile health apps – Some smartphone apps can detect irregular heartbeats. While not a substitute for professional diagnosis, these apps can prompt people to seek medical advice. More research is needed to understand exactly how they can be used to detect arrhythmias.

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