Atrial Fibrillation (AFib)

Atrial fibrillation (AFib or AF) is a heart condition where your heart beats irregularly and rapidly. 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. 

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 cause complications such as blood clots, stroke, heart failure and other heart-related issues. It can affect people of all ages, but it is more common in older people. Managing AFib properly and making heart-healthy lifestyle choices can help reduce these risks.

If you have AFib, you may not notice any symptoms. This is why it’s important to learn about the risk factors and have regular screenings, especially as you get older. Finding AFib early and managing it properly can reduce the risk of complications and improve your quality of life.

What are the symptoms of AFib?

With AFib, you may not always notice symptoms. If you do, they may range from mild to severe. Common symptoms are:

• 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, seek medical attention promptly right away, even if the symptoms are mild or they come and go. 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.

Seek immediate medical care for:

• 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 AFib?

Atrial fibrillation could be caused by:

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

What are the risk factors for AFib?

These factors put you at higher risk for atrial fibrillation: 

• Age: Your heart changes as you age, and you’re more likely to have other risk factors as you get older. Your risk is higher if you are over age 65. 
• Family history: A family history of AFib or other heart rhythm disorders may make it more likely that you develop the condition.
• Lifestyle factors: Tobacco use, illegal drug use, taking stimulant medications and drinking alcohol, especially binge drinking, can increase your risk.
• Stress: Chronic stress or anxiety may affect your body’s hormone balance and make your nervous system more active.
• Electrolyte imbalances: Calcium, magnesium, potassium and sodium help your heart beat properly. Changes in their levels could cause AFib.

Making heart-healthy choices, such as maintaining a balanced diet, exercising regularly, quitting smoking, limiting alcohol and managing stress, can help prevent AFib and other heart problems.

If you’re at risk for AFib, talk to your health care provider about screening and how to prevent blood clots that may result from this condition. Early diagnosis can make a significant difference in managing the condition and improving your quality of life.

Learn more about diagnosing and treating atrial fibrillation.