Atrial Fibrillation (Afib, AF) Warning Symptoms and Signs

  • Medical Author:
    William C. Shiel Jr., MD, FACP, FACR

    Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

  • Medical Editor: John P. Cunha, DO, FACOEP
    John P. Cunha, DO, FACOEP

    John P. Cunha, DO, FACOEP

    John P. Cunha, DO, is a U.S. board-certified Emergency Medicine Physician. Dr. Cunha's educational background includes a BS in Biology from Rutgers, the State University of New Jersey, and a DO from the Kansas City University of Medicine and Biosciences in Kansas City, MO. He completed residency training in Emergency Medicine at Newark Beth Israel Medical Center in Newark, New Jersey.

Atrial Fibrillation and Stroke

Atrial fibrillation is a risk factor for stroke. About 15 percent of all people who have strokes have AFib. Signs and symptoms of a stroke are:

  • Vision loss or changes
  • Confusion
  • Numbness, weakness, or tingling on one side of the body
  • Trouble speaking
  • Vertigo

What is atrial fibrillation?

Atrial fibrillation (Afib, AF) is a disturbance of the rhythm of the heartbeat (arrhythmia), a type of heart rhythm disorder.

To understand how atrial fibrillation occurs, let's first understand the normal rhythm of the heart, and how the electrical activation of a heartbeat occurs. In a person with a healthy heart, the rhythm of the heartbeat is initiated by electrical activation of the natural pacemaker of the heart - the sinoatrial node (SA node). From there, the electrical activity spreads along natural pathways through the two chambers of the top of the heart (atria), then to the ventricles that pump the blood out into the circulation. The uniform contraction of the atrium that is generated by the electrical stimulation of the heart muscle of the atrium, causes the atrium to contract, passing blood into the ventricle where it can then be pumped out into the circulation.

Afib occurs when the top chambers of the heart fire with electrical activity that is completely chaotic throughout the atrium, without really forming a uniformly contracting atrium to pass blood down into the ventricles. The random electrical activity throughout the atrium connects randomly to the ventricle. This leads to what is referred to as an irregular heart rhythm of this common condition. Afib can cause the ventricle to contract irregularly at rates ranging from 100 to 200 beats per minute.

The irregularity of the heart contractions in Afib account for all of the symptoms caused by the disease. This condition is a type of heart disease.

What are the signs and symptoms of atrial fibrillation?

Very often people with Afib have no signs or symptoms, and do not know they are in atrial fibrillation. Those who notice when they are having atrial fibrillation can have signs and symptoms ranging from mild to debilitating.

Symptoms of this heart condition include:

What does atrial fibrillation feel like?

A person with atrial fibrillation that causes no symptoms - causes no abnormal feelings or sensations. However, when a person experiences symptoms and signs of this type of heart disease, one of the most common symptoms is a feeling of the heart beating rapidly. It also can feel like the heart is fluttering in the chest with palpitations as the heart beats irregularly. Because the chambers of the heart are beating irregularly, they do not adequately fill with blood before contracting. This causes insufficient oxygen distribution throughout the body, which can lead to:

  • Lightheadedness and dizziness, which may cause the person to fall from near fainting when they are upright.
  • There can be a general sensation of weakness in the legs as well as an overall uneasy feeling
  • Overall fatigue is commonly associated with shortness of breath.
  • Ascending stairs or walking uphill this can make any movement difficult for a person with this health condition. There can be chest awareness and chest discomfort. Sometimes people with this disease wake up in the night with chest awareness (consciously noticing the organs within the chest that you normally are not aware of), palpitations, and anxiousness.
  • The person can be sweating and a have a feeling of not being well.

Some people with early atrial fibrillation may have minimal symptoms. Often it is short-lived and the normal heart rhythm is restored. Later, this heart condition can occur more frequently, and for a longer duration of each episode. This is when signs and symptoms the person may be experiencing can be even more pronounced, and treatment may be necessary.

Who is at risk for atrial fibrillation?

There are several risk factors for this condition. For example, a patient who has, or has a history of:

Are heart attack or stroke symptoms different from atrial fibrillation symptoms?

A person that has chest discomfort or pain with Afib could be having a heart attack. It is not possible to distinguish the cause of the chest discomfort or pain without a complete medical evaluation, including an electrocardiogram (EKG, ECG).

Atrial fibrillation can lead to stroke from a blood clot in the heart dislodging and going to the brain. Four signs of stroke include:

  1. Sudden onset slurring of speech
  2. Face drooping
  3. Drooling
  4. Weakness or numbness in an extremity

Afib, stroke, and heart attack are medical emergencies and the person who is ill should be seen by a doctor for treatment immediately.

Medically Reviewed by a Doctor on 1/30/2017

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