AFib (AF), Atrial fibrillation, Healthcare, Heart Diseases

Atrial Fibrillation Diagnostics Guide: EKG Interpretation, Common Misdiagnosis, and More

Guidance on how to diagnose AFib

Estimates show that between 2.7 million and 6.1 million people in the United States have atrial fibrillation (AFib), the most common type of treated heart arrhythmia. The number of AFib cases is likely to go up as the U.S. population ages. Also as people are not sure how is afib diagnosed.

The diagnosis of AFib can be tricky, and the condition is often misdiagnosed.

In this post, we will take you through the simple AFib diagnostics guide. Read on to learn more.

How is AFib Diagnosed?

How is AFib diagnosed
How is atrial fibrillation diagnosed?

Before we discuss how is AFib diagnosed, it’s important to emphasize the importance of patient-reported symptoms.

Doctors encourage patients to describe symptoms regardless of how insignificant they may see to them. 

In addition to symptoms, the doctor also reviews a patient’s medical history and carries out a physical exam. Various tests are necessary to diagnose the problem and rule out other conditions.

These tests include:

  • Electrocardiogram (EKG or ECG) – is the most important AFib diagnosis tool. Small electrodes are attached to the chest and arms to sense and record electrical signals traveling through the heart. However, that’s not the only way how to do that. Now you can also measure your ECG anywhere anytime with portable ECG devices and using your smartphone. These solutions within simple, fast, and effective heart measurements detect signs of existing or potential AFib risks.
  • Echocardiogram – sound waves that create moving pictures of a heart.
  • Holter monitor – portable EKG device a patient carries in the pocket or wears as a shoulder strap or belt so it can monitor heart activity for 24 hours or longer.
  • Event recorder – portable EKG device that monitors a heart over a few weeks or months.
  • Blood tests – to rule out other conditions such as thyroid disease.
  • Stress test (exercise testing) – performing tests on the heart while a patient is exercising.
  • X-ray – chest x-ray displays condition of heart and lungs, helps rule out other conditions.

Can EKG Detect Arrhythmia?

As seen above, EKG is the primary testing tool for AFib. Therefore, it’s understandable to wonder if EKG can detect arrhythmia effectively.

As the go-to test for diagnosis of AFib, EKG can detect arrhythmia, but misdiagnoses are possible. 

Evidence shows that primary care practitioners may not always detect AFib on EKG. High accuracy is achievable through adequate training. Human interpretation is still the best way to analyze EKG results.

Computer software is not currently sensitive enough to be used alone in the diagnosis of AFib and other forms of arrhythmia on EKG.

EKG Interpretation

Guidance on how is afib diagnosed

Before you read about AFib EKG, let’s define the terms you’ll see:

  • P-waves – atrial depolarization of the left and right atrium and corresponds to atrial contraction.
  • Atrium (plural atria) – upper heart chamber.
  • Flutter waves – atria beat regularly, but faster than usual.
  • AV node – part of the heart’s electrical conduction system that coordinates its top; electrically connects ventricles and atria.
  • QRS complexes – central and most visually obvious part of EKG tracing i.e., the main spike in the EKG line.

The greatest indicator of AFib EKG is the absence of P-waves and irregular ventricular rate.

The baseline consists of either F-waves (fibrillatory waves) or minute oscillations. 

The P-waves don’t show up on EKG because of a fast atrial rate of 400-600 beats per minute. As a result, the action potentials are of low amplitude.

Fibrillatory waves on EKG are small. Their morphology varies, and frequency is high. The amplitude of F-waves ranges from small to large. It’s important not to mistake large F-waves for flutter waves. Flutter waves are observed in atrial flutter. Although they may appear similar at first, the F-waves vary in morphology while flutter waves are almost always identical. 

The ventricular rate in AFib EKG is irregular (100-180 beats per minute). Factors that influence the ventricular rate are:

  • Age
  • Active medications
  • Concomitant AV-blocks

In AFib, the atrioventricular (AV) node is refractory and allows a certain number of atrial action potentials to make it to the ventricles. This makes the ventricular rate irregular. The QRS complexes produced when atrial action potentials reach ventricles appear irregular or abnormal too. The frequency of QRS complexes doesn’t have a specific pattern.

AFiB EKG doesn’t have visible P-waves, and it’s indicated by an irregular QRS complex.

The ventricular rate is fast unless you’re on AV nodal blocking medications. F-waves are usually detected.

AFib Misdiagnoses 

AFib misdiagnosis is common, which is why doctors don’t rely on EKG only but order some other tests to rule out other conditions. This is why your doctor may ask to mention any changes you’ve been experiencing. 

Atrial fibrillation is often mistaken for the following health problems:

  • Tachycardia and other arrhythmias – tachycardia is a condition where the heart beats more than 100 times per minute. The meaning of the word “tachycardia” is “an abnormal heart rhythm.” This means that AFib is a form of tachycardia, which is why it’s easy to mistake it for other forms of arrhythmias and similar conditions.
  • Anxiety and panic attacks – intense feelings of nervousness, fear, and discomfort can cause shortness of breath and a rapid heart rate that makes people think AFib is the reason.
  • Hyperthyroidism (Graves’ disease) – excessively high thyroid hormone levels overstimulate metabolism, which leads to racing heart and palpitations. 
  • Underlying heart conditions – some heart diseases such as heart valve disorder and coronary artery disease can lead to AFib. Management of symptoms of AFib requires treatment of the underlying heart condition. 

Importance of Proper Diagnosis

Guidance on how is afib diagnosed

Symptoms of AFib are similar to those of other health conditions where the heartbeat becomes irregular. However, a proper diagnosis of AFib is vital. 

If left unmanaged, AFib can increase the risk of stroke and heart failure.

The chaotic heart rhythm of AFib can lead to blood clotting in the atria. A blood clot can dislodge from the heart and travel to the brain. In the brain, a blood clot blocks blood flow, and stroke occurs.

Misdiagnosis of AFib leaves a patient without proper treatment. Gradually AFib can weaken the heart and lead to failure.

Preventing AFib

To avoid this condition you need to not only know how is AFib diagnosed but also how to reduce the risk of AFib:

  • Quit smoking.
  • Eat a heart-healthy diet.
  • Exercise regularly.
  • Manage stress.
  • Get enough sleep.
  • Limit intake of alcohol and caffeine.
  • Maintain weight in a healthy range.


Atrial fibrillation is a common but manageable problem. Adequate treatment of AFib requires an accurate diagnosis. Misdiagnoses are possible because rapid heartbeat is present in many health conditions. The primary diagnosis tool is EKG, but other tests may also be necessary to rule out other medical problems.

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