Atrial Fibrillation: Investigations and Diagnosis

Medically Reviewed by Dr. K on 19 April 2021

Diagnosis of Atrial Fibrillation

AF, or atrial fibrillation, may or may not cause symptoms. It may be an incidental finding during a routine physical examination. You could also schedule an appointment if you have symptoms such as fluttering, irregular pulse, or fatigue.

If your doctor suspects you have it, they'll start by listening to your heart. With a stethoscope, they might be able to detect abnormal heartbeat. If not, they can recommend tests to confirm the diagnosis, determine what's causing it, and identify the best treatment option for you.

AF is often diagnosed by the primary care or family doctor. However, your doctor may refer you to a:

  • Cardiologist, a doctor who specializes in heart diseases and conditions
  • Electrophysiologist, a doctor who specializes in arrhythmias

Medical Exam

When you schedule an appointment with your doctor or a specialist to see whether you have atrial fibrillation, find out if there is something you need to do ahead of time. For example, you can be required to fast prior to blood tests.

To maximise your time with the doctor, be prepared to explain the symptoms and their timing. Make a list of all of your medications, including supplements and over-the-counter medications. Also, have details about your own and close family members' medical histories on hand.

Make a list of any questions you have for your doctor, such as:

  • What may be the cause of my symptoms?
  • What types of tests will I require?
  • What are the treatments that are suggested for my condition? Are there any other effective options?
  • Do I need to make some lifestyle changes?

During your examination, the doctor will ask you specific questions about:

  • Symptoms
  • Lifestyle
  • Personal medical history
  • Family medical history

During the physical exam, they are likely to:

  • Listen to the pace and rhythm of your heartbeat
  • Take your pulse and blood pressure readings
  • Listen to your lungs

ECG Monitoring

Yes, indeed. The most useful test for diagnosing AF is this simple, painless test. It tracks the electrical activity of your heart. It is capable of displaying the:

  • Rate of your heartbeat
  • Rhythm of your heartbeat
  • Strength and timing of electrical signals passing through your heart

Electrodes are tiny patches that a doctor or technician puts on various parts of the body, including some on your chest. These detect signals that result in wave patterns on ECG results. It provides a description of your heart's total electrical activity to your doctor.

A normal ECG, on the other hand, will not always detect AF because the test is a snapshot. To keep track of your ticker for a longer period of time, you can need a portable heart rhythm monitor.


Holter Monitor

You wear this device for 24 to 48 hours as it continuously monitors the electrical activity of your heart. The extra time increases the probability of detecting an irregular heart rhythm, also known as an arrhythmia.

Small electrodes will be connected to your chest, just as with a normal ECG. These electrodes are connected by wires to a small recorder that you can clip to your belt, hold in your pocket, or wear around your neck.

Then you just go about your business as usual. Later, the doctor will review the reported results.


Event Monitor

This functions similarly to a Holter monitor, except it, only monitors the heart's rhythm at specific times, normally for 30 days. When it detects an error, it will begin recording automatically. You may have to press a button if you're feeling:

  • Dizzy
  • Weak
  • Lightheaded
  • A racing or fluttering heart

It's possible you'll have to wear it for a month or more, depending on how long it takes to catch and record the problem.

Mobile Cardiac Telemetry (MCT)

Mobile cardiac monitoring is a term you might hear. This tiny gadget is worn all the time and tracks your heart as you go through your everyday activities. The majority of them send a Bluetooth signal to a data center, which analyses the data and sends a report to your doctor.

Stress Test

It's just what it sounds like: a test that puts the heart under extra strain to see how it reacts to working hard and beating fast. During the exam, you'll be hooked up to an ECG, and the technician will monitor your heart rate and blood pressure.

Exercising is a simple way to get the heart rate up. You may use a stationary bicycle or a treadmill to walk or run. This is why it's often referred to as a treadmill test.

You may take a special drug that makes the heart pump faster if your body can't manage physical exercise.


This test creates a moving image of your heart using sound waves and a monitor. An echo provides details to your doctor about:

  • The size and shape of your heart
  • How well the heart muscle and valves are working
  • Where the heart muscle isn't contracting the right way

Transthoracic echocardiogram (TTE). Your doctor will see an image of your heart with this imaging test. The doctor uses an ultrasound transducer to send out and read sound waves that bounce off the heart's walls and valves. The information is used by a computer to make a video of your heart. Your doctor will check the size of your heart, how well it functions, the condition of your heart valves, and whether you have any blood clots.

Transesophageal echocardiogram (TEE). Your doctor will see an image of your heart with this imaging test. The doctor uses an ultrasound transducer to send out and read sound waves that bounce off the heart's walls and valves. The information is used by a computer to make a video of your heart. Your doctor will check the size of your heart, how well it functions, the condition of your heart valves, and whether you have any blood clots.

Blood Tests

These can help your doctor figure out what's triggering your AF. Infections, thyroid and kidney disorders, symptoms of a heart attack, and other conditions can be detected by blood tests.

Portable Electrocardiogram

This is referred to as a handheld ECG. It may also resemble a wristwatch. It has electrodes on the back that measure the pulse at the wrist or chest. A department shop, a drugstore, or the internet are all good places to look for one. The doctor can advise you to do it so you can take a fast reading if you have a symptom. Your ECG data will be saved in its memory for your doctor to review.

Fitness Trackers

AF can be detected by common smartwatches equipped with special sensors known as photoplethysmographic sensors (or PPGs).

Electrophysiology Study

An electrophysiology study (EPS) will help your doctor find out what's causing your irregular heartbeat and how to handle it effectively.

A small, flexible electrode is inserted into a blood vessel leading to your heart, usually in the neck or groin, by your cardiologist. The electrode is then guided to your heart using an imaging device. The electrode will then calculate the electrical signals in your heart.

Before the surgery, the doctor will give you a numbing medication to prevent you from feeling pain. You may also be prescribed a sedative to help you relax. The procedure can take 1-4 hours, and you'll spend the next 4-6 hours in a recovery room.


Referenced on 14/4/2021

  1. National Heart, Lung, and Blood Institute: “Atrial Fibrillation,” “How is Atrial Fibrillation Diagnosed?"
  2. American Heart Association: “Cardiac Event Recorder,” “Common Tests for Arrhythmia."
  3. Northwestern Memorial Hospital: “Atrial Fibrillation Express Test."
  4. Medscape: “Atrial Fibrillation Workup: Lab Studies."
  5. Medical Devices: Evidence and Research.
  6. Heart Rhythm Society: “Artificial Intelligence Automatically Detects Atrial Fibrillation Using Apple Watch’s Heart Rate Sensor,” “Benefits of monitoring patients with mobile cardiac telemetry (MCT) compared with the Event or Holter monitors,” “Diagnosing Atrial Fibrillation (AF),” “New Study Show Popular Smart Watches Accurately Measure Rapid Heart Beat.”
  7. Current Treatment Options in Cardiovascular Medicine: “Role of Magnetic Resonance Imaging in Atrial Fibrillation Ablation.”
  8. Heart Rhythm: “2017 ISHNE-HRS expert consensus statement on ambulatory ECG and external cardiac monitoring/telemetry.”
  9. Mayo Clinic: “Tilt table test,” “Atrial fibrillation," “EP study."
  10. iproc: “Screening of Atrial Fibrillation Using Wrist Photoplethysmography from a Fitbit Tracker.”
  11. Johns Hopkins Medicine: “Electrophysiologial Studies."

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