Atrial Fibrillation (irregular heart beat)

Atrial fibrillation, often shortened to AF or Afib, is an irregular and often fast heart rhythm. The two top chambers of the heart quiver instead of squeezing in a steady beat, so blood moves less cleanly through them. Some people feel a fluttering or racing pulse and get very tired, and others feel nothing at all and learn about it during a routine check.

What atrial fibrillation is, and what it is not

Atrial fibrillation is not simply a case of nerves or too much coffee. It is a fault in the electrical signalling of the heart, and it matters mainly because of what happens to the blood. When the top chambers quiver, blood can pool and form a clot, and if that clot travels to the brain it can cause a stroke. Heart & Stroke reports that about 20% of ischemic strokes are attributed to atrial fibrillation, and about a quarter of strokes after age 40 are linked to it.

It is also not a condition you can judge by how you feel. Episodes come and go, and clots can form during episodes you never notice, which is why Canadian guidelines base decisions about blood thinning on your overall stroke risk profile rather than on how often symptoms show up. Age is the strongest factor: atrial fibrillation affects under 1% of people below age 50, about 4% at age 65, and about 12% of people aged 80 and older.

Signs and symptoms

• A racing, fluttering, pounding or skipping heartbeat
• Shortness of breath, especially with activity
• Unusual tiredness or lack of energy
• Chest discomfort or pressure
• Lightheadedness, dizziness or feeling faint
• Trouble concentrating, anxiety or sweating
• No symptoms at all, with the rhythm found by chance during a check up

Episodes vary in length and in how much they bother people. Some last minutes, some last days, and the same person can go from barely noticing the rhythm to finding it hard to tolerate. Quiet months followed by a cluster of episodes is a familiar pattern, and it is worth keeping a simple record of when they happen.

What raises the risk

Some risk factors cannot be changed:

• Getting older, which is the strongest factor
• Existing heart conditions such as heart failure, coronary artery disease, heart valve problems, or previous heart surgery
• An overactive thyroid, and a family history of atrial fibrillation

Others can often be worked on, usually with support from a health care team:

• High blood pressure, which is the most common contributing condition
• Heavy or regular alcohol use
• Living with obesity, and untreated sleep apnea
• Diabetes, and low physical activity

How atrial fibrillation is diagnosed in Canada

The diagnosis is made by recording the heart rhythm, usually with an electrocardiogram, or ECG, in a clinic or emergency department. Because the rhythm can come and go, Canadian doctors often add a Holter monitor worn for a day or more, an event or patch monitor worn for weeks, or an implanted loop recorder. An echocardiogram, which is an ultrasound of the heart, and blood tests including thyroid function are commonly ordered as well, to look for causes and to plan care. Because a single recording can easily miss an intermittent rhythm, more than one attempt is sometimes needed before the diagnosis is confirmed.

Treatment and day-to-day management

Clinical research for Atrial Fibrillation (irregular heart beat) is enrolling. See the current studies ↓

Care usually has three parts: lowering the risk of stroke, settling the rate or the rhythm, and treating the conditions that feed the arrhythmia. Depending on your risk profile and how you feel, a health care team may discuss:

• Anticoagulant medicines, including direct oral anticoagulants and warfarin, chosen after a stroke risk assessment
• Rate control medicines such as beta blockers, calcium channel blockers and digoxin
• Rhythm control medicines, known as antiarrhythmics
• Procedures including electrical cardioversion, catheter ablation, left atrial appendage closure, and pacemakers
• Attention to contributing conditions, including blood pressure, sleep apnea, alcohol intake, weight and physical activity

These choices depend on your own history, and they get revisited over time. What happens next is a conversation between you and your own clinician, and nothing here is a recommendation about any specific option.

When to talk to a doctor

• Call 911 for sudden face drooping, arm weakness, trouble speaking, a sudden severe headache, or sudden vision loss. These are signs of stroke, and people with atrial fibrillation are at higher risk.
• Call 911 for chest pain, fainting, or severe shortness of breath along with a racing or irregular heartbeat.
• Contact your doctor promptly if you notice a new irregular pulse, or if episodes become longer, more frequent or harder to tolerate.

Why clinical research matters for atrial fibrillation

Two questions remain unsettled: how to prevent strokes related to atrial fibrillation without raising the risk of bleeding, and when rhythm control should be offered rather than rate control. Studies now recruiting include factor XI and factor XIa inhibitors as a newer class of anticoagulant, left atrial appendage closure compared with drug therapy, earlier and newer forms of ablation including pulsed field ablation, and screening programs that use wearables and single-lead ECG devices to find silent atrial fibrillation. Others are testing structured risk factor programs covering weight, alcohol, sleep apnea and blood pressure as part of routine care.

Every one of those questions is settled in a clinical study, not in an office. Taking part is voluntary, you give informed consent before anything begins, and you can stop at any time without affecting the care you get from your own doctor. No one can promise in advance that a study will help you personally.

Learn more from Canadian sources

• Heart & Stroke: atrial fibrillation
• Canadian Cardiovascular Society atrial fibrillation guidelines
• Public Health Agency of Canada: heart diseases and conditions
• Canadian Stroke Best Practices