About Atrial Fibrillation

Atrial fibrillation is one of the most common heart rhythm abnormalities in the United States. Up to 5 percent of the population older than 65 years has atrial fibrillation. However, atrial fibrillation is not solely the disease of the elderly. Many patients may present with atrial fibrillation even as early as their teenage years. The normal rhythm of the heart (otherwise known as sinus rhythm) is generated in the upper right chamber of the heart called the right atrium. Sinus rhythm is conducted through the heart in an organized fashion similar to a wave emanating from a pebble dropped into a puddle. Sinus rhythm then travels to the left upper chamber called the left atrium and then to the bottom heart chambers called the ventricles.

Atrial fibrillation is an abnormal heart rhythm due to chaotic and disorganized electrical activity in the top chambers of the heart, or atria. Imagine, instead of a single organized wave from a single pebble dropped in a puddle that several pebbles are dropped into a puddle simultaneously, with waves traveling in all directions and with waves crashing into each other. Atrial fibrillation can cause rapid and irregular heartbeats that can be very uncomfortable. Atrial fibrillation also can cause many other symptoms including chest pain, shortness of breath, dizziness, fatigue and fainting. If rapid atrial fibrillation is left untreated, it may result in weakening of the heart muscle. However, the symptoms that an individual may experience with atrial fibrillation are quite varied. Some individuals may have minimal to no symptoms while some individuals may have nearly debilitating symptoms. Depending on an individual’s symptoms, and co-existing cardiac and medical conditions, many different treatment options are available to alleviate the symptoms or to cure atrial fibrillation.

What causes atrial fibrillation?
There is no simple answer to this question. Recent research has discovered that in a large proportion of individuals atrial fibrillation is triggered or even maintained by extra beats arising from the pulmonary veins. The pulmonary veins are the vessels that drain blood from the lungs and return the blood to the left atrium. Tissue from the left atrium that connects to the pulmonary veins seems to, in patients with atrial fibrillation, be electrically “irritable.” This causes extra beats to fire, triggering atrial fibrillation. Many other risk factors for atrial fibrillation exist including high blood pressure, coronary artery disease, cardiac valve abnormalities, congestive heart failure and an overactive thyroid, among others.

In addition to the symptoms that atrial fibrillation may cause, atrial fibrillation is the leading cause of stroke arising from the heart in the United States. The risk of stroke per year may be as little as less than 1 percent to as high as 15 percent depending on co-existing risk factors. Due to the disorganized and chaotic electrical rhythm of the atria, the atria no longer contract effectively. This leads to stagnant blood flow in the atria, predisposing a blood clot to form in the atria. Dislodgement of the blood clot causes the stroke. Effective treatments are available to help reduce the risk of strokes with atrial fibrillation.