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Atrial fibrillation

Atrial fibrillation (Afib or AF) is a condition involving an irregular heart rhythm, known as an arrhythmia. It is the most common type of arrhythmia, affecting approximately 350,000 Canadians. Generally, the risk of developing atrial fibrillation increases with age and with other risk factors such as diabetes, high blood pressure, and underlying heart disease. One of the main complications of atrial fibrillation is stroke. Individuals with atrial fibrillation have a risk of stroke that is 3 to 5 times greater than those without atrial fibrillation.

What is atrial fibrillation?


Atrial Fibrillation: Are you at risk of atrial fibrillation?


Atrial refers to the top two chambers of the heart known as the atria, where the irregularity in atrial fibrillation occurs. Afib falls under a larger category of illnesses called arrhythmias, which are electrical disturbances of the heart. Arrhythmias can also occur in the ventricles, the two chambers below the atria, and these tend to be more serious than arrhythmias affecting the atria.

The atria (the heart's "collecting chambers") are designed to send blood efficiently and rhythmically into the ventricles (the "pumping chambers") by way of regular electrical signals. From there, blood is pumped to the rest of the body. In Afib, the electrical signals are rapid, irregular and disorganized, and the heart may not pump as efficiently.

Afib can cause the heart to beat very fast, sometimes more than 150 beats per minute. A faster than normal heartbeat is known as tachycardia.

Most people with Afib lead active, normal lives with treatment. Untreated Afib can interfere with your quality of life. Talk to your doctor if you have Afib but continue to feel unwell.

Atrial fibrillation has different forms

  • Paroxysmal Afib: a temporary, sometimes recurrent condition. It can start suddenly and then the heart returns to a normal beat on its own, usually within 24 hours, without medical assistance.
  • Persistent: Afib for more than seven days The heart continues to beat irregularly, and will require either medical or electrical intervention to return the heart to a normal rhythm.
  • Permanent Afib: the irregular beating of the heart lasts for more than a year when medications and other treatments have failed. Some people with permanent Afib do not feel any symptoms or require medications.

Often, the cause of atrial fibrillation is not known. Causes include: 

  • High blood pressure, the most common cause
  • Abnormal structure of the heart
  • Infection or inflammation of the heart (myocarditis or pericarditis)
  • Diseases that damage the valves of the heart
  • Overactive thyroid (hyperthyroidism)
  • A blood clot in the lung (pulmonary embolism)
  • Congenital heart disease
  • Excessive use of alcohol

Some people with Afib may feel fine. They may not even know they have the condition until they have a routine test called an electrocardiogram. Others may experience various symptoms including:

  • Irregular and fast heartbeat
  • Heart palpitations or a rapid thumping in their chest
  • Chest discomfort, chest pain or pressure
  • Shortness of breath, particularly with exertion or anxiety
  • Fatigue
  • Dizziness, sweating or nausea
  • Light-headedness or fainting

If you are experiencing any of these symptoms, visit your doctor.

If you have been diagnosed with Afib, your doctor can help you determine the best way to treat your symptoms and risk.

If you are experiencing chest discomfort or other signs of a heart attack , call 9-1-1 or your local emergency number immediately.

Ask your doctor to check your pulse on a regular basis.


If your pulse is fast and your heartbeat is irregular, your doctor may have you checked for Afib. Your doctor will take your medical history, and will ask you for details about your condition and risk factors.

Questions may include:

  • How long have you had symptoms? Describe your symptoms. Do they come and go?
  • Do you have other medical conditions?
  • How much alcohol do you drink?
  • Does anyone in your family have Afib
  • Do you have heart disease or a thyroid condition.

Your age is also a factor as Afib is more common in older people.

Your doctor will listen for fast, irregular beats, using a stethoscope. Your doctor will also check your pulse and determine whether or not it is normal.

Other tests include:


Your doctor will customize your treatment based on your risks, medical profile, needs and preferences, and how much the symptoms are interfering with your quality of life.

Most people with A-fib will likely have to take blood thinners in order to reduce the risk of stroke. The risk of stroke depends on several other risk factors, including the presence of heart muscle weakness, having high blood pressure or diabetes, being over 75 years of age, or having had a previous stroke or a mini-stroke (TIA) .Your doctor may prescribe blood thinners such as an anti-platelet like ASA (Aspirin®) or an anticoagulant to prevent clots from forming and travelling to the brain.

There are two general treatment strategies - rhythm control and rate control. Your doctor will decide which strategy is best for you based on your symptoms and other factors.

  • Rhythm control These treatments attempt to prevent an irregular heartbeat by restoring and maintaining a normal, regular heartbeat. The first approach involves taking medications that attempt to prevent the Afib from occurring. Occasionally, some patients require electrical cardioversion. This is a controlled electric shock to the heart to restore a normal rhythm. On rare occasions, medications and electrical cardioversion do not work. You may be referred to a specialist and considered for an electrophysiology study and catheter ablation, to stop the Afib from recurring (see below).
  • Rate control Almost every patient with atrial fibrillation will be prescribed a medication that is designed to slow the heart rate during Afib. For some, this type of medication is enough to control the symptoms.

When taking medications of any type, it is important to follow your doctor or pharmacist's instructions. Establish a routine for taking your pills, and keep to your daily schedule. Do not share medications with others, and do not stop taking your medication without consulting your doctor. Report any side effects to your doctor. He or she may change the dosage or type of medication to prevent or reduce any side effects.

Electrophysiology Studies (EPS) and Catheter Ablation On rare occasions, patients with Afib who do not respond to medications or electrical cardioversion require an EPS in order to stop Afib from recurring. The objective of EPS testing is to locate the cause of irregular electrical impulses in the heart. Catheter ablation is then performed to destroy, through tiny burns, the electrically chaotic tissue in the heart. During EPS and catheter ablation, thin wires (or catheters) are introduced to the heart through veins in the leg and neck. Radiofrequency energy is sent through the catheters to the parts of the heart where the irregular electrical impulses are located. Ablation essentially creates scars in the heart that stabilize any electrical short circuits.

Read more about heart disease treatment

Can those under 60 have atrial fibrillation?

If you develop and do not have any structural heart disease, this is considered idiopathic (or lone) atrial fibrillation. Idiopathic Afib usually occurs before the age of 60.

Researchers have identified a handful of genes that predispose families to Afib. Once all these genes are identified, researchers may be able to develop new treatments for this condition. Those who have a genetic predisposition to Idiopathic Afib may develop the disease in their 30s and 40s. It is also possible for young people without Afib in their family to develop the disease.

Living with Atrial Fibrillation

Mel, Christine and others tell their story of Afib


Healthy lifestyle changes are always a good idea. Your risk for developing many diseases can be reduced by a healthy diet, not smoking, limiting alcohol intake and reducing stress have been shown to improve health in numerous studies. Any lifestyle changes that lower blood pressure (such as maintaining a normal weight) are likely to reduce the chances of developing atrial fibrillation.

It may be possible to prevent Afib by staying physically active. A large study of people over the age of 65 found that participating in light to moderate physical activities, particularly leisure-time activities such as gardening and walking, were associated with significantly lower incidence. Even if you have Afib, it is important to stay physically active because doing so has a positive impact on your overall health. Consult your doctor before you become more physically active.

Visit your doctor regularly to have your Afib monitored. Do not attempt to monitor your own heart rhythm by using expensive, high-tech equipment you may find on the internet. Using such products may unnecessarily elevate stress.

If you have high blood pressure, ask your doctor how to monitor your own blood pressure at home.

1 in 3

One-third of all strokes after age 60 are caused by Afib.

Is there a connection between atrial fibrillation and stroke?

Afib increases your risk of stroke. It is estimated that up to 15% of all strokes are caused by atrial fibrillation. This risk increases with age, so that after age 60, one-third of all strokes are caused by Afib. Also, individuals with atrial fibrillation have 3 to 5 times greater risk for ischemic stroke.

With a normal heart rhythm, the heart receives electrical signals from the brain via the sinoatrial (SA) node. The SA node sends impulses to the atria which instructs them to beat. The impulses then make their way to the lower chambers of the heart (the ventricles), which pump blood to the rest of the body.

During Afib, the atria contract chaotically and in a disorganized manner. Because the atria don't move blood properly, blood pools and gets stuck in the grooves of the heart. This may result in the formation of blood clots, which could get pumped to the brain and result in an ischemic stroke. An ischemic stroke is caused when blood flow to the brain is interrupted by a clot in one of the blood vessels within, or leading to, the brain. Studies show that long-term use of the blood thinner warfarin in patients with Afib can reduce the risk of stroke by 70 to 80%.

Related information

Atrial Fibrillation Ablation (Hamilton Health Sciences)

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