Atrial fibrillation is a heart disorder, most often found in older adults. During atrial fibrillation, the heart's two small upper chambers quiver rather than beating effectively. As a result, blood isn't pumped completely out of the chambers, so it can pool and clot.

Approximately 2.2 million Americans suffer from atrial fibrillation. The likelihood of developing this disorder increases with age. Doctors estimate that three to five percent of those over age 65 have this disorder.

Atrial fibrillation can be dangerous because, if a piece of a blood clot in the atria leaves the heart and becomes lodged in an artery in the brain, a stroke can result. In fact, about 15% of all strokes occur in people with atrial fibrillation.

There are several ways to treat atrial fibrillation. The most common treatments include:

• Medications, which slow down the rapid heart rate associated with atrial fibrillation.

• Electrical cardioversion - This is basically an electric shock that restores normal rhythm. It is typically used when medications don't improve symptoms.

• Drugs can sometimes restore the heart's normal rhythm. These drugs are given under medical supervision, and are delivered through an IV tube into a vein, usually in the patient's arm.

• Radiofrequency ablation may be effective in some patients when medications don't work. In this procedure, thin and flexible tubes are introduced through a blood vessel and directed to the heart muscle. Then a burst of radiofrequency energy is delivered to destroy tissue that triggers abnormal electrical signals or to block abnormal electrical pathways.

• Surgery can be used to disrupt electrical pathways that generate atrial fibrillation.

• Pacemakers can be implanted under the skin to regulate the heart rhythm.

Who's At Risk for Atrial Fibrillation?

We don't really know what causes atrial fibrillation, but we do understand some of the risk factors. The most significant are:

• Increased age - the number one risk factor is simply old age

• Coronary heart disease

• High blood pressure

• Abnormal heart muscle function

• Disease of the mitral valve between the left and right ventricle

• An overactive thyroid gland

• Low amounts of oxygen in the blood. This is often found in patients with lung diseases like emphysema or chronic obstructive pulmonary disease.

• Inflammation of the lining surrounding the heart

• Blood clots in the lung

• Chronic lung disease

• Alcoholism

• Stimulant drug use - abuse of drugs like cocaine or decongestants

• Recent heart or lung surgery

• Congenital heart disease

In addition, there are young adults who have atrial fibrillation without any known cause or any evidence of underlying heart disease. This condition is known as lone atrial fibrillation. Stress, alcohol, tobacco and the use of stimulants is believed to play a role in lone atrial fibrillation. Does Caffeine Cause Atrial Fibrillation?

One question that has been asked by many people is whether caffeine contributes to atrial fibrillation, and whether caffeine consumption is safe for those with atrial fibrillation.

One study, reported by the UK Tea Council, suggests that caffeine consumption is safe for those at risk for the disease. This study, conducted in Denmark, examined nearly 48,000 participants, each over the age of 56. Their caffeine consumption was analyzed over a period of years, as was their health information, including whether or not they went on to develop atrial fibrillation.

The study concluded that caffeine consumption was not at all related to whether or not participants developed the heart disorder. The associated researchers did not recommend that those at risk for atrial fibrillation discontinue the consumption of caffeine.

This is great news, especially for green tea drinkers. Since green tea is known to be associated with a lower than average risk of heart disease, it's wise for those at risk of any sort of cardiovascular disease to consume green tea on a daily basis. And, while green tea is lower in caffeine than coffee, black tea and soda, it does contain some caffeine.

So, you're safe to drink your green tea, both for its health benefits and its delicious and refreshing flavor. If you're not a connoisseur of green tea yet, take a look at all the benefits that green tea can offer.

• Green tea is full of anti-oxidants - which are known to reduce aging and prevent disease.

• Green tea has been shown to decrease your risk of heart disease by improving your cholesterol. While green tea doesn't actually reduce the cholesterol in your blood, it does appear to prevent the bad cholesterol from hardening into the plaque that causes narrowing of the arteries.

• Green tea has been associated with a lower risk of many forms of cancer. It is believed that green tea's anti-oxidants act as a scavenger to abnormal cells, ridding the body of them before they can mutate into cancer cells.

• Green tea has been shown to naturally regulate blood glucose levels, which may help maintain normal weight and may be helpful in controlling Type II diabetes

• Green tea has been shown to have anti-microbial properties, which means that it may be helpful in ridding the body of infections.

So, if you haven't been drinking green tea, see what you've been missing? Not only is green tea delicious, inexpensive and readily available, but it may also be an important way to prevent disease and protect your health.