What is Atrial Fibrillation or AFib?
Atrial fibrillation is the most common sustained heart rhythm in the United States, affecting about 3 million Americans. Instead of beating normally, the upper chambers quiver or fibrillate. The upper chambers no longer fill the lower chambers with blood, and heart output can be reduced by 20-40%. During atrial fibrillation, the upper chambers send about 600 impulses a minute down to the lower chambers. While the lower chambers do not beat 600 times a minute, they can still beat very fast and irregularly. Over time, this can cause the important lower pumping chambers to fail. Possibly the worst complication of atrial fibrillation is stroke. When the upper chambers stop contracting, blood can stagnate and form a clot. This clot can break off and go anywhere in the body, including the brain. 75% of strokes associated with atrial fibrillation leave a patient in a nursing home or are fatal.
Atrial fibrillation that lasts more than 48 hours will put a patient at risk for stroke. The stroke risk is 5% per year for ongoing atrial fibrillation. The stroke risk becomes higher for older patients. Generally, the risk of stroke can be lowered to 1% per year or less with oral blood thinners such as Coumadin, Pradaxa, or Xarelto. There is an additional 1% per year risk of serious bleeding with blood thinners, but generally, the benefits outweigh the possible complications for most people. Pradaxa may be slightly superior to coumadin, which was the standard for many years. The use of coumadin (also called warfarin) requires frequent monitoring with lab work to make sure the blood is not too thick or too thin. Xarelto and Pradaxa do not have this monitoring requirement.
Atrial fibrillation patients may be converted back to normal sinus rhythm with medications, electrical cardioversion (shock), or they may convert spontaneously on their own. It is important that their blood be therapeutically thin for 3 weeks prior to cardioversion or that blood thinner be started, and clot ruled out with a transesophageal echo.
Atrial fibrillation always comes back at some point, and 9 out of 10 patients cannot tell when an episode of atrial fibrillation first starts. Their presenting symptom may be shortness of breath/heart failure or even a stroke several weeks after their abnormal rhythm begins. There are ways of checking daily for atrial fibrillation, but no method is 100% accurate. After a person is converted back to normal rhythm, it is critical that they remain on blood thinners for at least one month and, in most cases, much longer. There is still a significant stroke risk after the heart converts back to normal from a clot dislodging. Individual treatment for atrial fibrillation depends on many factors and should be discussed with your cardiologist/electrophysiologist.
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