What is atrial fibrillation and what can happen to me if I have it?

During a regular heartbeat, the top two chambers of the heart (the atria) send out an electrical signal that triggers the heart to pump blood through the body. Atrial fibrillation happens when the electrical signal becomes irregular and causes disorganized and rapid contractions of the atria. These abnormal atrial contractions may cause ineffective pumping of blood through the body.

What are the signs and symptoms of atrial fibrillation?

Although the signs and symptoms of atrial fibrillation can be different from person to person, the most common symptom is an irregular heart beat. Other symptoms can include:

• fast heart rate
• chest pain
• shortness of breath
• fatigue
• dizziness
• faintness.

What causes atrial fibrillation?

Atrial fibrillation happens to some people for no apparent reason. In others, atrial fibrillation can be triggered by a reversible cause such as:

• alcohol intake
• physical or emotional stress
• stimulant medications
• heart surgery or heart attack
• inflammation of the sac around the heart (pericarditis)
• overactive thyroid gland (hyperthyroidism)
• a blood clot in the lung (pulmonary embolism).

Atrial fibrillation can also be a recurring or chronic problem caused by:

• high blood pressure (hypertension)
• coronary artery disease
• diseases of the heart valves or heart muscle.

How is atrial fibrillation diagnosed?

If your pulse is fast (usually greater than 100 beats per minute) and has an irregular beat, your doctor may think you have atrial fibrillation. A painless test that shows a graph of the electrical activity of the heart, called an electrocardiogram (ECG), can confirm whether or not you have atrial fibrillation. You may also be asked to wear a Holter monitor, which is a small portable device that records and saves a series of ECGs over a specific time period (usually 24 hours).

How serious is atrial fibrillation?

Atrial fibrillation isn't usually life-threatening or considered serious in people who are otherwise healthy. However, atrial fibrillation can be dangerous if you have diabetes, high blood pressure or other diseases of the heart. Either way, this condition needs to be properly diagnosed and managed by a doctor.

Atrial fibrillation does increase the risk of stroke, especially in people who are over the age of 65, have had a previous stroke or who have high blood pressure, diabetes or congestive heart failure. Because the blood in the atria doesn't completely empty if you have atrial fibrillation, it can pool and blood clots can form. Sometimes a blood clot will break away and travel to the brain where it can cause a stroke.

How do I manage atrial fibrillation?

Your doctor will develop a plan to manage your atrial fibrillation based on the options that are best for you. Some options include:

• medications to control heart rate and rhythm
• medications to "thin the blood"
• controlled electric shocks to the heart (called cardioversion)
• a procedure (called ablation) to destroy the area of the heart that is causing the electrical malfunction or to limit heart rate.

Additional resources

• Atrial fibrillation - British Columbia Ministry of Health, Information, Privacy and Records Branch
• Atrial fibrillation - Capital Health (Edmonton)
• Atrial fibrillation & flutter causes & risk factors - Heart Rhythm Society

Prepared by Alberta Health Services. This FAQ appeared originally on the Canadian Health Network Web site.