General Atrial Fibrillation Facts

• In atrial fibrillation (A Fib), the electrical signals that coordinate the muscle of the upper chamber (atria) of the heart become rapid and disorganized; resulting in an irregular heartbeat (arrhythmia), often greater than 300 beats per minute. In atrial flutter (AFL), a single electrical wave circulates very rapidly in the upper chambers.
• A Fib is the most common sustained heart rhythm disorder and increases the risk for heart disease and stroke, both leading causes of death in the United States. An estimated 2.2 million adults in the United States have been diagnosed with atrial fibrillation.¹
• A Fib and AFL usually are not life-threatening if treated properly.
• The likelihood of developing these arrhythmias increases with age. After age 65, between three and five percent of people have A Fib.
• A Fib may last a short time and end spontaneously (paroxysmal A Fib) or it may continue indefinitely (persistent or permanent A Fib).
• Many patients with paroxysmal A Fib eventually develop permanent A Fib.
• The signs and symptoms of A Fib vary, and may include a sudden flutter of the heart, anxiety, shortness of breath, weakness and difficulty exercising, chest pain, sweating, dizziness or fainting.
• A Fib may have no known cause, or it may be related to coronary heart disease, thyroid disease, high blood pressure, structural defects of the heart and its valves, lung disease or other disorders.
• A Fib is diagnosed by electrocardiogram (ECG), or with devices that are worn by the patient to monitor the heart over time (Holter monitor and event recorders).
• A Fib may increase the risk of blood clots and stroke. Medications can be prescribed to prevent the blood clots from forming.
• A Fib sometimes requires treatment with medications, controlled electric shocks to the heart, or procedures that destroy the heart tissue that gives rise to the irregular heart rhythm. Less often, a pacemaker or another device is implanted to monitor and control the heart’s rhythm.

Atrial Fibrillation Overview

Atrial fibrillation (also called AF or A Fib) is a common heart rhythm disorder caused by a problem in the conduction of electrical impulses in the upper chambers, or atria, of the heart. A Fib and other rapid heartbeats that arise in the atria, or in the juncture between the atria and the lower chambers (ventricles) are called "supraventricular tachycardias." Although A Fib is not life threatening it can lead to other rhythm problems, such as chronic fatigue and congestive heart failure.

More than 2 million people in the United States have A Fib, and about 160,000 new cases are diagnosed each year. A Fib is uncommon among young people, although it can occur in people of any age. The likelihood of developing the conditionincreases with age. After age 65, between three and five percent of people have atrial fibrillation. Approximately nine percent of people over age 80 have the condition.

Types of A Fib

Paroxysmal A Fib — Episodes of A Fib that end spontaneously are called paroxysmal A Fib. This type of atrial fibrillation usually comes on suddenly, and its symptoms can range from mild to severe. The irregular heart rhythm may last for a few seconds, minutes, hours or longer before the heart resumes a normal rhythm on its own.

Persistent A Fib — With this condition, the irregular heart rhythm continues indefinitely unless it is treated.

Permanent A Fib — In this situation, normal rhythm cannot be restored.

Causes of A Fib

In A Fib, the electrical signals that coordinate the muscle of the upper chambers (atria) of the heart become rapid and disorganized, typically causing the atria to beat faster than 300 beats per minute. (The normal rate when the heart is at rest is about 60 to 80 beats per minute). When this happens, the atria may contract poorly and no longer effectively force blood into the lower chambers (ventricles). As a result, the flow of blood to the body may be reduced.

If treated appropriately, atrial fibrillation and atrial flutter seldom cause serious or life-threatening problems.

Risk of Stroke

According to the Framingham Heart Report, people with A Fib or Atrial Flutter have a three to five times greater risk of stroke, especially if they are over 65, have already had a stroke, or have high blood pressure, diabetes or congestive heart failure.

During an episode of A Fib, the heart muscle does not contract normally to force open the heart valves that pass blood from the atrium to the ventricle. The valve opens passively, but some blood may not enter the ventricle as it should. Instead, it pools in parts of the atrium, increasing the risk that clots will form in the stagnant blood.

Even small blood clots can cause problems if they leave the heart and are released into the general circulation. They may clog arteries in the body and disrupt the blood supply to vital organs. A stroke occurs when a clot lodges in the arteries that supply blood to the brain.

Signs and Symptoms

Individuals may feel the effects of A Fib differently. While some may feel a sudden flutter or tremor of the heart, others may feel nothing. Some patients may feel the exact moment when an irregular heartbeat starts and may experience a period of anxiety or fear. While not everybody notices an irregular heartbeat, the signs and symptoms of A Fib could be:

• Shortness of breath
• Weakness and difficulty exercising
• Chest pain
• Sweating
• Dizziness
• Fainting (syncope)

Treatments

Anti-arrhythmia medications can help to slow and stabilize the irregular heartbeat and prevent this arrhythmia from occurring again.

Furthermore, a relatively new procedure, called Catheter Ablation, can cure A Fib. During this procedure, one or more flexible tubes (catheters) are inserted via X-ray into the blood vessel and directed to the heart muscle. A burst of radiofrequency energy destroys the areas of tissue that create the abnormal electrical signals responsible for the irregular heartbeat.

What to ask your doctor

If you have been diagnosed with A Fib, or suspect that you may have this disorder, you may want to ask your doctor the following questions:

What is the cause of my A Fib?

• How can I be sure I have A Fib or AFL and not a more serious hearth rhythm disorder?
• Will my condition go away on its own?
• What are the risks factors for A Fib?
• Am I at increased risk for having a stroke?
• What are my treatment options?
• What are the risks and side effects of medications to control my condition, or to reduce the risk of stroke?
• What are the risks/benefits of other treatment options?
• Should I see an electrophysiologist (a specialist in heart rhythm disorders)?

¹ Go, AS, Hylek, EM, Phillips KA, Chang, Y, Henault LE, Selby JV, Singer DE. Prevalence of diagnosed atrial fibrillation in adults. National implications for rhythm management and stroke prevention: the Anticoagulation and Risk Factors In Atrial Fibrillation (ATRIA) Study. JAMA 2002;285:2370-2375.