Atrial fibrillation (AF) is a major public health concern in the United States, affecting an estimated 2.3 million Americans. The prevalence of AF is projected to reach 5.6 to 12.1 million by the year 2050. AF is the most common sustained arrhythmia seen in clinical practice and accounts for approximately one-third of hospitalizations for cardiac dysrhythmias.
Atrial fibrillation is characterized by uncoordinated atrial activation with resulting deterioration of atrial mechanical function. While AF can occur in isolation, it may also be associated with other arrhythmias such as atrial flutter or atrial tachycardia. Atrial fibrillation can be paroxysmal, persistent, or permanent. The 2014 American College of Cardiology/American Heart Association/Heart Rhythm Society AF guidelines defines paroxysmal AF as recurrent AF that terminates spontaneously or with intervention within 7 days of onset, persistent AF as one that is sustained beyond 7 days, and permanent AF as long-standing AF in which restoring and/or maintaining sinus rhythm has failed or has been foregone. Long-standing persistent AF is usually defined as AF that persists for over 1 year. Long-standing persistent and permanent AF is more commonly seen in older patients with structural heart disease.
A number of factors have been associated with increased risk of AF. The prevalence of AF increases with age; it affects 8 to 10 percent of patients 80 years of age and older. AF is also more common in males: data from the Framingham Heart Study suggest that men are 1.5 times as likely to develop AF than are women after controlling for age and comorbidities. Obesity increases the risk of developing AF. Data from community-based cohorts suggest that obese patients have a 1.5- to 2.3-fold greater risk of developing AF. Furthermore, obesity increases the likelihood that AF will progress from paroxysmal to permanent AF. Additional factors associated with an increased risk of AF include smoking, hypertension, hyperthyroidism, obstructive sleep apnea, diabetes, myocardial infarction, heart failure, and cardiac surgery.
AF is associated with significant mortality, morbidity, and health care costs. Patients with AF have a twofold greater risk of death than do those without this disease. AF is associated with an increased risk of stroke, which affects 5 percent of nonrheumatic AF patients and nearly 7 percent of AF patients with heart failure each year. Furthermore, ischemic stroke that occurs in the setting of AF tends to be either fatal or of moderate to high severity in most patients. AF can also cause a number of cardiac conditions, including myocardial ischemia or infarction, exacerbation of heart failure, and cardiomyopathy if the ventricular rate is insufficiently controlled. Although some patients with AF are asymptomatic, other patients experience symptoms like shortness of breath, intractable fatigue, and near-syncope, which can severely affect overall quality of life. In total, the management of AF and its complications costs the U.S. health care system approximately $26 billion each year.
