Atrial fibrillation involves the rapid ineffective beating of the atria. Cardiac output is reduced leading to weakness, fainting and breathlessness. Stagnant blood in the atria can form clots and lead to stroke.

Atrial fibrillation is the rapid and uncontrolled beating of the atria, the upper chambers of the heart, and is the most common cardiac arrhythmia. It can result from congestive heart failure, myocardial infarction, valvular disease, hypertension, infection, or, in 20 to 35% of cases, without any evidence of other cause. It affects nearly 2.3 million people in the United States and 4.5 million people in the developed world. From 200,000 to 400,000 new cases are diagnosed each year and the size of the AFib population is expected to more than double by mid century. It was the primary cause of 399,000 hospitalizations in the U.S. in 2000; this represents a 1.7- fold increase in only 15 years.

Patients with AFib experience palpitations, chest discomfort, weakness, fainting and breathlessness. Their quality of life can be so severely reduced that in one study the average quality of life was equivalent to that of patients crippled from rheumatoid arthritis and below that for patients with congestive heart failure or recent myocardial infarction. AFib, if untreated, can permanently damage the heart causing heart failure and death.

Patients with AFib have a severely elevated risk of stroke (5% risk of stroke per year or 5 to 6 times the risk of the general population). In the U.S. approximately 100,000 strokes per year are due to AFib. Moreover, the strokes associated with AFib are generally more severe, have a greater chance of causing long-term neurological deficits and are twice as likely to result in death.

Because of the risk of stroke, patients require lifelong treatment with anticoagulants. This involves two office visits per year and monthly blood tests to measure clotting rates. Even so, such therapy only reduces the stroke risk by two-thirds, (to double the risk of those without AFib), and carries a 2.4% yearly risk of major hemorrhage.

Atrial fibrillation is an expensive disease. In the Framingham study, adjusted total Medicare spending for those with AFib was 8.6 to 22.6 times higher for men and 9.8 to 11.2 times higher for women. Just the cost of maintaining a patient on anti-coagulation therapy is $3,000 per year; including treatment of resultant hemorrhage, this increases to $7,000 per year.

Atrial fibrillation is believed to be a progressive disease. Initially it is “ paroxysmal ” – consisting of isolated, self-terminating episodes. Over time these episodes tend to become more frequent and longer in duration. Eventually, the continued presence of AFib provokes changes or “remodeling” in the atrial tissue that make the tissue more susceptible and better able to maintain the arrhythmia. At this point it will become “ persistent ,” requiring electrical or drug cardioversion to restore normal sinus rhythm. Finally it becomes “ permanent ” (also called “ chronic ”) when it can no longer be terminated by cardioversion. It is estimated that 30% of patients have permanent AFib.

A general practitioner may treat patients with atrial fibrillation especially if the AFib is paroxysmal and recurrence rates are low. However, if the symptoms are frequent or severe, or if the AFib becomes persistent, patients are generally referred to a cardiologist or an electrophysiologist for evaluation and treatment.