What is atrial fibrillation?

Causes and Symptoms

Atrial fibrillation, also called A-Fib or AF, may occur with or without heart abnormalities, but commonly there is an underlying heart condition. Patients with atrial fibrillation often have a stiffening of the arteries, aortic stenosis, or enlargement of the left ventricle. Also, hypertension (high blood pressure) is a predisposing factor of this conduction irregularity. Other risk factors include aging, obesity, sleep
apnea, diabetes, and myocardial infarction (heart attack). An accurate model to describe the cause of atrial fibrillation is one recognizing the interdependence between genetics, the heart’s response to risk factors, and aging.

Atrial fibrillation is usually characterized by electrical conduction abnormalities seen on an electrocardiogram (ECG or EKG), which analyzes the heart’s rhythm. Three common conduction abnormalities are intermittent, persistent, and permanent.

The disease is characterized by a variety of symptoms, and some patients are without symptoms. A patient might describe feeling either a slow heartbeat (for example, heart “pauses”) or a fast heartbeat. Other symptoms that may occur during an atrial fibrillation episode are shortness of breath, lightheadedness or dizziness, fatigue, and chest discomfort.

Treatment and Therapy

There are generally three treatment categories for atrial fibrillation: acute, subacute, and chronic. The primary goal of therapy, when possible, is restoring the heart to a sinus rhythm. Additionally, treatments focus on preventing thromboembolic complications of atrial fibrillation and rate control.

If the patient is experiencing acute atrial fibrillation, then the causative factors should be addressed. Often, electrical cardioversion is still the treatment of choice. Heart rates often are controlled effectively with medications such as beta-blockers, calcium channel blockers, or digoxin. Rare complications including embolic stroke may result because of the lack of proper blood flow in the atria coincident with the abnormal contractions (fibrillation). Anticoagulants (blood thinners) such as aspirin or warfarin are used to prevent stroke. In some instances, ablation therapy, antiarrhythmic medications, or the Maze procedure (which creates new electrical pathways through the heart using scar issue) may be used.

Lifestyle changes such as trigger avoidance and regular exercise may help patients avoid recurrences of acute atrial fibrillation.

Perspective and Prospects

It is projected that atrial fibrillation will continue to increase in incidence worldwide over the next few decades. Therefore, improvements in both the classification and the characterization of the disease are imperative. Refining the understanding of genetics, such as chromosome 4 variants, offer prospects for intervention. Stroke prevention, comprehensive treatment including both rate and rhythm control, and management of underlying conditions may also help mitigate atrial fibrillation.

Bibliography

A.D.A.M. Medical Encyclopedia. "Atrial Fibrillation or Flutter." MedlinePlus, June 22, 2012.

Camm, A. John, Thomas F. Lüscher, and Patrick W. Serruys, eds. The ESC Textbook of Cardiovascular Medicine. 2d ed. New York: Oxford University Press, 2009.

Fauci, Anthony S., et al. Harrison’s Principles of Internal Medicine. 18th ed. New York: McGraw-Hill Medical, 2012.

Fox, C. S., et al. “Parental Atrial Fibrillation as a Risk Factor for Atrial Fibrillation in Offspring.” JAMA: Journal of the American Medical Association 291, no. 23 (2004): 2851–2855.

Mosby’s Medical Dictionary. 8th ed. St Louis: Mosby, 2009.

Wood, Debra, and Michael J. Fucci. "Atrial Fibrillation." Health Library, November 9, 2012.