Atrial Fibrillation (AFib)

What is atrial fibrillation (AFib)?

Atrial fibrillation (AFib) is a common heart rhythm disorder that causes an irregular and often rapid heartbeat. A normal resting heart rate is 60 to 100 beats per minute. With AFib, it can range from 100 to 175 beats per minute. AFib is the most common abnormal heart rhythm problem. 

How does atrial fibrillation affect your heart?

To understand AFib, it helps to know how the heart muscle works. There are four chambers of the heart. There are two upper chambers, called atria, and two lower chambers, called ventricles.  

The heart’s upper right chamber contains a cluster of cells called the sinoatrial node (SA node). Every time your heart beats, a signal starts at the SA node. It then travels to the other chambers to make them contract and push blood out to the body.

Normally, these signals keep your heart contracting in a regular rhythm. In AFib, your heart’s electrical signals don’t always work correctly. The heart’s upper chambers (atria) quiver instead of contracting properly, leading to irregular heartbeats.

AFib can lead to complications, including:

• Blood clots
• Increased risk of stroke
• Heart failure
• Other heart-related issues

While AFib can affect people of all ages, it’s more common in older adults. Managing it properly and making heart-healthy lifestyle choices can help reduce your risks.

Why is early detection of AFib important?

Some people with AFib don’t notice any symptoms. That’s why it’s important to know the risk factors and have regular heart health screenings—especially as you get older.

Finding AFib early and managing it can lower your risk of serious complications and improve your quality of life.

What are common symptoms of atrial fibrillation?

You may not have symptoms at all. When symptoms do appear, they can range from mild to severe.

Common AFib symptoms include:

• Heart palpitations: A rapid, irregular heartbeat or fluttering sensation in the chest. It may last for a short or long time. You may feel concerned or uncomfortable.
• Shortness of breath: You may feel breathless or have trouble breathing, especially during physical activity or when you’re lying flat. That’s because AFib may make it harder for your heart to pump oxygen-rich blood throughout your body.
• Fatigue or weakness: Feeling tired or weak may make it hard to do daily tasks and reduce your quality of life.
• Dizziness or lightheadedness: You may feel dizzy or lightheaded when you stand up quickly or exert yourself physically. 
• Chest pain: This symptom is less common than other symptoms. It may be mild or severe and may last a short or long time.

If you have any symptoms of AFib, see your health care provider, even if the symptoms are mild or happen occasionally. A health care provider may use tests, such as a Holter monitor, to record your heart’s electrical activity over time and help diagnose abnormal heart rhythms like AFib. Starting treatment right away can help manage it and lower your risk of complications.

When to seek emergency medical care

Call 911 or get immediate help if you experience:

• Severe chest pain or pressure
• Fainting or loss of consciousness
• Trouble breathing or shortness of breath that gets worse rapidly
• Rapid or irregular heartbeat along with weakness, confusion or trouble speaking

What causes atrial fibrillation?

Afib can be caused by a variety of health conditions or underlying issues, including:

• High blood pressure (hypertension): High blood pressure may strain the heart and cause changes in its structure and electrical system.
• Heart conditions: Conditions like coronary artery disease, heart valve disorders, heart defects at birth and heart surgery can affect the heart’s structure or function.
• Thyroid problems: Thyroid disorders like hyperthyroidism (overactive thyroid) can change the body’s metabolism and heart function.
• Other health conditions: Sleep apnea, viral infections, obesity, diabetes, kidney disease, lung disease, pneumonia or complications after surgery may cause AFib.

Who is at risk for atrial fibrillation?

Several factors can raise your risk of developing AFib:

• Age: Risk increases with age, especially after age 65.
• Family history: A family history of AFib or heart rhythm disorders may increase your chances.
• Lifestyle factors: Tobacco use, stimulant drugs and alcohol—especially binge drinking—can all trigger AFib.
• Stress and anxiety: Chronic stress may disrupt hormone levels and stimulate your nervous system.
• Electrolyte imbalances: Low or high levels of potassium, sodium, calcium or magnesium can affect your heartbeat.

How can you reduce your risk of AFib?

Making heart-healthy choices can help prevent AFib and lower your risk of related complications:

• Eat a balanced diet
• Exercise regularly
• Quit smoking
• Limit alcohol
• Manage stress
• Monitor other health conditions like high blood pressure or diabetes

If you're at risk, talk to your health care provider about AFib screening and how to reduce your risk of blood clots or stroke.

Learn how Banner Health can help you manage atrial fibrillation

At Banner Health, we provide expert care for atrial fibrillation, starting with the right diagnosis and a care plan tailored to your needs. Our team includes cardiologists and heart rhythm specialists who offer a range of treatments — including medications, cardioversion and catheter ablation — to help control your heart rhythm and lower your risk of stroke and other complications.

Whether you're newly diagnosed or looking for long-term management, we’re here to help you protect your heart health and live well.

Explore AFib diagnosis and treatment options at Banner Health