Atrial Fibrillation

Atrial fibrillation, also referred as atrial fib or afib for short, is one of the most common heart rhythms in the United States.


It is an abnormal heart rhythm (arrhythmia or irregular heart beats) that originates in the top chambers of the heart called atria(1). This is due to a defect in the electrical mechanism that comes from the heart’s own pacemaker called the sinoatrial node (SA node). Instead of the electrical impulses traveling in an orderly fashion, they travel to the atria at the same time causing the atria to contract in an irregular, disorganized, chaotic, and rapid manner(2).



Atrial fib can appear in different patterns(2).
  • Intermittent (paroxysmal): The heart develops atrial fib and returns back to normal (sinus) rhythm and the episodes may last from seconds to days.

  • Persistent: Atrial fib occurs in episodes, but it doesn't return to sinus rhythm and medical treatment is needed to bring the heart rate to a regular rhythm.

  • Permanent: The heart is always in atrial fib. Conversion back to sinus rhythm either is not possible or is not appropriate for medical reasons.

    atrial fibrillation
    Atrial fibrillation(4)


    A common problem that occurs from afib is clot formation inside the atria. For this reason, most people who have this arrhythmia are on blood thinners. If a clot becomes dislodged and travels to the lungs via the pulmonary artery, it may result as a pulmonary embolism (PE) resulting in severe breathing difficulties. If it travels to the brain, it can cause a stroke.

    Atrial fibrillation causes(3)
    Most people who have atrial fib suffer from heart disease and some have coronary heart disease (hardening of the arteries). Other people have different heart problems like:

  • Long-term elevated blood pressure (hypertension)
  • Abnormal heart valves
  • Pericarditis, inflammation of the lining that covers the heart (pericardium)
  • Pumping function abnormalities of the heart
  • Problems with the heart's natural pacemaker, the SA node



    According to Mayo Clinic, One-third of the people who have atrial fib don't have underlying heart disease and the cause is often unknown, it is believed that possible causes include(3):

  • An overactive thyroid or other metabolic imbalance damage or microscopic abnormalities in the muscles of the atria.

  • Abnormal electrical properties of groups of heart cells

  • emphysema, or other lung diseases

  • Exposure to heart stimulants, such as caffeine, tobacco or alcohol





    1. Cleveland clinic, “What is atrial fibrillation?“ Available at: http://my.clevelandclinic.org/heart/atrial_fibrillation/afib.aspx. Accessed December 6, 2008

    2. EMedicineHealth, “Atrial fibrillation overview.“ Available at: http://www.emedicinehealth.com/atrial_fibrillation/article_em.htm. Accessed December 6, 2008

    3. Mayo clinic, “Atrial fibrillation.” Available at http://www.mayoclinic.org/atrial-fibrillation/causes.html. Accessed December 6, 2008

    4. Ems academy, "cardiology Part 2." Available at http://www.ems-academy.biz/CEUModules/httpsdocs/cardiology_part_2%20test.htm. Accessed December 7, 2008



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