What Are the Early Signs and Symptoms of AFib?

What Are Some Other Warning Signs of AFib?

While the most noticeable symptoms of AFib can be obvious, there are also lesser-known signs of AFib. These early signs of AFib that can occur are based on numerous considerations like genetics and ethnic background, age, cardiac risk factors, and the type of AFib along with its primary cause.

Some of these other signs and symptoms of AFib are:

  • AFib reduces the amount of oxygen carried to the brain. The incomplete contractions of the atria don’t push their full volume of blood to the ventricles, which means that the ventricles are then unable to move enough oxygen-rich blood out to the rest of the body.A decreased amount of oxygen to the brain will lead to confusion along with impairment in cognitive abilities.
  • Throat tightness. Some individuals report the sensation of mild constriction in their throat and being able to feel their heart rate in that area.
  • Dizziness. As with confusion, a less than normal level of oxygen flow to the brain will cause dizziness, lightheadedness, and fainting.
  • Shortness of breath. AFib limits cardiac output, which decreases the transport of a healthy level of oxygen to the lungs. If you have AFib, you can experience shortness of breath with little or no activity.
  • Weakness or feeling faint. You can experience weakness at rest or during activity because your body’s muscles aren’t receiving the oxygen they need for fuel to perform at full strength.
  • Tiredness with exercise or activity. Reduced exercise tolerance is typical for people who have AFib. The heart’s standard response to physical activity is to increase its pumping speed to move more blood out to the working muscles to supply their increased demand for oxygen to fuel increased physical activity levels. With AFib, your heart rate can increase beyond a reasonable response to increased exertion without delivering enough energy, thus producing a faster onset of exercise-induced fatigue.
  • A rapid and uncontrolled heart rate for more than a brief period can also lead to associated physiological responses such as increased sweating and nausea. Some people with certain types of AFib have also reported abdominal pain and an increased need to urinate.



Any of these signs or symptoms can occur at rest or with different types of activity.

Warning signs of AFib worsen if you have other health problems like shortness of breath due to a respiratory issue, and active infection, hemorrhage, or sepsis. Significant emotional or physical stress and exhaustion from a lack of sleep can trigger or possibly worsen AFib symptoms.

Is it AFib or Something Else?

Some people describe AFib as a fluttering feeling, while others feel an ache or tightness. Palpitations can be soft or pronounced. In fact, symptoms can be so mild that you may not realize you have AFib until a doctor delivers the surprising news.

The point is that AFib can bear some resemblance to other conditions – some of which may occur simultaneously – including:

  • Anxiety or panic attack. The surge of adrenaline during an anxiety attack often leads to a full-body response, including painful or tight sensations in the chest and heart palpitations.
  • Lightheadedness or fatigue. Either of these issues can result from dehydration, a loss of blood volume, or generally poor physical conditioning.
  • Heartburn. Although many people will feel a “burning” sensation in their upper chest when too much stomach acid moves up the esophagus, heartburn could also manifest as pain (some may even mistake it for a heart attack).
  • Hyperthyroidism. When the thyroid gland produces too much thyroid hormone, it stimulates your metabolism, leading to anxiety, irritability, and hypertension. In some people, hyperthyroidism can also lead to heart palpitations, a rapid heart rate, and breathlessness.
  • Heart attack. The difference in symptoms between the two conditions is that AFib often occurs suddenly with a fluttering feeling and chest palpitations, whereas a heart attack starts gradually and includes intense chest pain that can spread to the shoulders, arms, back, up into the neck and jaw, and in some instances the abdominal region. Although having a heart attack can cause AFib, but the arrhythmia will not lead to a heart attack.
  • Heart disorders. Not surprisingly, other heart disorders can mimic AFib, particularly sinus arrhythmia, and various forms of tachycardia. In fact, a heart valve disorder or coronary artery disease could be the source of your AFib and will need to be diagnosed and dealt with before your AFib symptoms can be eliminated.
  • Other physiologic ailments. Conditions such as anemia, an electrolyte imbalance, changes in hormones, or low blood glucose levels can also cause specific symptoms seen with AFib.

Keep in mind that even if you don’t have any symptoms, the fact that you have AFib places you at a five times higher likelihood for stroke than someone with no history of AFib.

Because of this circumstance, people with AFib need to understand the signs and symptoms of stroke, which include drooping on one side of your face, arm weakness on one side, and difficulty speaking or understanding someone who is talking. If any of these symptoms occur at any time, you need to call 911 immediately.

Although only a qualified medical professional can provide an accurate diagnosis, certain symptom sets most likely point to AFib instead of one of these mimicking conditions.

For instance, a sudden, severe, and short-lived response could signal a major event like a heart attack, or perhaps an anxiety attack; AFib is often marked by fluctuating symptoms, cycles of “episodes” that eventually end and begin again (unless you live with permanent AFib).

How Is AFib Diagnosed?

The AFib diagnosis procedure is relatively straightforward. If your symptoms are persistent and you suspect you may be in AFib most of the time, your doctor will first conduct an electrocardiogram (EKG or ECG) to evaluate your heart rhythm over the course of a few minutes.

However, If your symptoms come less frequently, you may instead wear a Holter monitor for 24 to 48 hours in order to catch the next AFib episode.

Your doctor can also order a chest x-ray and echocardiogram to assess your heart function and see if there are any unusual problems such as a reduced pumping capacity often known as heart failure.

There are a variety of other tests that can be helpful if these initial investigations don’t show any problems. The key is to be clear and thorough when you report the symptoms you are experiencing and when they appear to your doctor, so they have a good idea of how your AFib may be triggered or aggravated.

The more detailed you can describe how your symptoms affect your life, the more personal and targeted your testing and treatment plan will be.

Your blueprint will take into account your previous medical history, your age and specific genetics, the presence of any other underlying cardiac conditions or risk factors that would cause them, and the type of AFib you have.

Not all individuals who have AFib experience symptoms. According to a study in the American Heart Association journal Circulation from 2012, roughly 15 to 30 percent of people with AFib show no signs of the condition.

In some cases, AFib doesn’t appear until a person has a routine EKG, other medical procedure that requires heart rhythm monitoring, or after a stroke.

When to See a Doctor

If you feel any of the adverse signs or symptoms mentioned earlier, seek medical attention as soon as possible. Early detection of AFib will give your healthcare team the best chance of developing an effective treatment plan before your condition worsens.


StopAfib.org (How Atrial Fibrillation Progresses)

MedicineNet (Patient Comments: Atrial Fibrillation – Symptoms and Signs)

Health.com (11 Surprising Symptoms of Acid Reflux)

Right Diagnosis (Misdiagnosis of Atrial Fibrillation)

Centers for Disease Control and Prevention (Atrial Fibrillation Fact Sheet)

Heart.org (What are the Symptoms of Atrial Fibrillation – Afib or AF?)

WebMD (Signs and Symptoms of Atrial Fibrillation)

Mayo Clinic (Atrial fibrillation – Symptoms and causes)

Heart Rhythm Society (Symptoms and Warning Signs)

Thrombosis Advisor (Signs and Symptoms of Atrial Fibrillation)

AHA Journals (Symptoms and Functional status of Patients With Atrial Fibrillation)

University of Michigan – Michigan Health (Other Conditions With Symptoms Similar To Atrial Fibrillation)

Journal of the American College of Cardiology (2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation)

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Angela FinlayAngela Finlay

Angela is a freelance writer and blogger committed to learning, understanding and communicating about the matters that affect daily life. From fitness and lifestyle, pregnancy and medical ailments, she has covered a range of health topics throughout her web writing career, contributing to major websites for over three years.

May 22, 2018
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