Atrial Fibrillation

Atrial Fibrillation is the most common arrhythmia. Over two million Americans are living with atrial fibrillation. Although it is not life-threatening, it can cause uncomfortable symptoms. It can also cause other problems such as congestive heart failure and stroke.

There are four chambers in the heart, two atria, which are the upper chambers of the heart, and two ventricles, which are the lower chambers of the heart. There is a right and left atrium and a right and left ventricle. An electrical impulse stimulates the heart muscle to contract. The normal electrical conduction starts in the sino-atrial (SA) node sending an impulse through the atria to the atrio-ventricular (AV) node, which is the relay station of the heart. It sends the electrical impulses to the ventricles. They are the major pumping structures of the heart.

With atrial fibrillation, there is an abnormal focus of electrical impulses that cause the atria to fibrillate or quiver rather than contract in a regular pattern. The storm of impulses is sent to the AV node, which conducts some of the impulses through to the ventricle. If the impulses are rapidly conducted the ventricular rate can be very fast.

Some people experience atrial fibrillation on and off, terminating without treatment and is classified as paroxysmal. Some people experience atrial fibrillation that needs to be terminated with some type of treatment to revert to normal sinus rhythm and that is classified as persistent. Some people are always in atrial fibrillation and even with treatment they stay in atrial fibrillation and that is classified as permanent.

Since the atria are not emptying properly when in fibrillation, blood clots can develop and travel (or embolize) to small vessels in the head and cause a stroke. It is important for people experiencing atrial fibrillation to be treated with an anticoagulant (drug that reduces the blood's ability to clot) such as Warfarin (Coumadin) or aspirin.