Symptoms of AFib may include:

• Feelings of a fast, fluttering or pounding heartbeat, called palpitations.
• Chest pain.
• Dizziness.
• Fatigue.
• Lightheadedness.
• Reduced ability to exercise.
• Shortness of breath.
• Weakness.

Some people with atrial fibrillation (AFib) don't notice any symptoms.

Atrial fibrillation may be:

• Occasional, also called paroxysmal atrial fibrillation. AFib symptoms come and go. The symptoms usually last for a few minutes to hours. Some people have symptoms for as long as a week. The episodes can happen repeatedly. Symptoms might go away on their own. Some people with occasional AFib need treatment.
• Persistent. The irregular heartbeat is constant. The heart rhythm does not reset on its own. If symptoms occur, medical treatment is needed to correct the heart rhythm.
• Long-standing persistent. This type of AFib is constant and lasts longer than 12 months. Medicines or a procedure are needed to correct the irregular heartbeat.
• Permanent. In this type of atrial fibrillation, the irregular heart rhythm can't be reset. Medicines are needed to control the heart rate and to prevent blood clots.

When to see a doctor

If you have symptoms of atrial fibrillation, make an appointment for a health checkup. You may be referred to a doctor trained in heart diseases, called a cardiologist.

If you have chest pain, seek immediate medical help. Chest pain could mean that you're having a heart attack.

To understand the causes of atrial fibrillation (AFib), it may be helpful to know how the heart typically beats.

The heart has four chambers:

• The two upper chambers are called the atria.
• The two lower chambers are called the ventricles.

Inside the upper right heart chamber is a group of cells called the sinus node. The sinus node makes the signals that starts each heartbeat.

The signals move across the upper heart chambers. Next, the signals arrive at a group of cells called the AV node, where they usually slow down. The signals then go to the lower heart chambers.

In a healthy heart, this signaling process usually goes smoothly. The resting heart rate is typically 60 to 100 beats a minute.

But in atrial fibrillation, the signals in the upper chambers of the heart are chaotic. As a result, the upper chambers tremble or shake. The AV node is flooded with signals trying to get through to the lower heart chambers. This causes a fast and irregular heart rhythm.

In people with AFib, the heart rate may range from 100 to 175 beats a minute.

Causes of atrial fibrillation

Problems with the heart's structure are the most common cause of atrial fibrillation (AFib).

Heart diseases and health problems that can cause AFib include:

• A heart problem you're born with, called a congenital heart defect.
• A problem with the heart's natural pacemaker, called sick sinus syndrome.
• A sleep disorder called obstructive sleep apnea.
• Heart attack.
• Heart valve disease.
• High blood pressure.
• Lung diseases, including pneumonia.
• Narrowed or blocked arteries, called coronary artery disease.
• Thyroid disease such as an overactive thyroid.
• Infections from viruses.

Heart surgery or stress due to surgery or sickness may also cause AFib. Some people who have atrial fibrillation have no known heart disease or heart damage.

Lifestyle habits that can trigger an AFib episode may include:

• Drinking too much alcohol or caffeine.
• Illegal drug use.
• Smoking or using tobacco.
• Taking medicines that contain stimulants, including cold and allergy medicines bought without a prescription.

Things that can increase the risk of atrial fibrillation (AFib) include:

• Age. The risk of AFib increases as you grow older.
• Caffeine, nicotine or illegal drug use. Caffeine, nicotine and some illegal drugs — such as amphetamines and cocaine — can cause your heart to beat faster. Use of these substances may lead to the development of more-serious arrhythmias.
• Drinking too much alcohol. Drinking too much alcohol can affect the electrical signals in the heart. This can increase the risk of atrial fibrillation.
• Changes in the level of body minerals. Minerals in the blood called electrolytes — such as potassium, sodium, calcium and magnesium — help the heart beat. If these substances are too low or too high, irregular heartbeats may occur.
• Family history. An increased risk of atrial fibrillation occurs in some families.
• Heart problems or heart surgery. Coronary artery disease, heart valve disease and heart problems present at birth increase the risk of AFib. A history of heart attack or heart surgery also makes a person more likely to get the condition.
• High blood pressure. Having high blood pressure increases the risk of getting coronary artery disease. Over time, high blood pressure may cause part of the heart to become stiff and thick. This can change how heartbeat signals travel through the heart.
• Obesity. People who have obesity are at higher risk of developing atrial fibrillation.
• Other long-term health conditions. You may be more likely to get AFib if you have diabetes, chronic kidney disease, lung disease or sleep apnea.
• Some medicines and supplements. Some prescription medicines and certain cough and cold remedies bought without a prescription can cause irregular heartbeats.
• Thyroid disease. Having an overactive thyroid gland can raise the risk of irregular heartbeats.

Blood clots are a dangerous complication of atrial fibrillation (AFib). Blood clots can lead to stroke.

The risk of stroke from AFib increases as you grow older. Other health conditions also may increase the risk of a stroke due to AFib. These conditions include:

• High blood pressure.
• Diabetes.
• Heart failure.
• Some types of heart valve disease.

Blood thinners are commonly prescribed to prevent blood clots and strokes in people with atrial fibrillation.

Healthy lifestyle choices can reduce the risk of heart disease and may prevent atrial fibrillation (AFib). Here are some basic heart-healthy tips:

• Control high blood pressure, high cholesterol and diabetes.
• Don't smoke or use tobacco.
• Eat a diet that's low in salt and saturated fat.
• Exercise at least 30 minutes a day on most days of the week unless your health care team says not to.
• Get good sleep. Adults should aim for 7 to 9 hours daily.
• Maintain a healthy weight.
• Reduce and manage stress.

You may not know you have atrial fibrillation (AFib). The condition may be found when a health checkup is done for another reason.

To diagnose AFib, the health care provider examines you and asks questions about your medical history and symptoms. Tests may be done to look for conditions that can cause irregular heartbeats, such as heart disease or thyroid disease.

Tests

Tests to diagnose atrial fibrillation (AFib) may include:

• Blood tests. Blood tests are done to look for health conditions or substances that may affect the heart or heartbeat.
• Electrocardiogram (ECG or EKG). This quick and painless test measures the electrical activity of the heart. Sticky patches called electrodes are placed on the chest and sometimes the arms and legs. Wires connect the electrodes to a computer, which prints or displays the test results. An ECG can show the heart rhythm and how slow or fast the heart is beating. It's the main test for diagnosing atrial fibrillation.
• Holter monitor. This small, portable ECG device records the heart's activity. It's worn for a day or two while you do your regular activities.
• Event recorder. This device is like a Holter monitor, but it records only at certain times for a few minutes at a time. It's typically worn for about 30 days. You usually push a button when you feel symptoms. Some devices automatically record when an irregular heart rhythm is detected.
• Implantable loop recorder. This device records the heartbeat continuously for up to three years. It's also called a cardiac event recorder. The device shows how the heart is beating while you do your daily activities. It may be used to see how often you have an AFib episode. Sometimes it's used to find rare episodes of AFib in those at high risk of the heart problem. For example, you may need one if you've had an unexplained stroke.
• Echocardiogram. Sound waves are used to create images of the beating heart. This test can show how blood flows through the heart and heart valves.
• Exercise stress tests. These tests often involve walking on a treadmill or pedaling a stationary bike while the heart is monitored. The tests show how the heart reacts to exercise. If you can't exercise, you may be given medicine that increases the heart rate like exercise does. Sometimes echocardiogram is done during a stress test.
• Chest X-ray. A chest X-ray shows the condition of the lungs and heart.

Following a heart-healthy lifestyle can help prevent or treat conditions that can lead to atrial fibrillation (AFib). The following changes are recommended to improve heart health:

• Eat healthy foods. Choose plenty of fruits, vegetables and whole grains. Limit sugar, salt and saturated fats.
• Exercise and stay active. Regular physical activity helps control diabetes, high cholesterol and high blood pressure — all risk factors for heart disease. Try to get 30 to 60 minutes of physical activity most days of the week. Talk to your health care team about the amount and type of exercise that's best for you.
• Don't smoke. Smoking is a major risk factor for heart disease. If you need help quitting, talk to your health care team.
• Maintain a healthy weight. Being overweight increases the risk of heart disease. Talk with your care provider to set realistic goals for weight.
• Control blood pressure. Get your blood pressure checked at least every two years if you're 18 and older. If you have risk factors for heart disease or are over age 40, you may need more-frequent checks. If you have high blood pressure, follow your treatment plan as directed.
• Get your cholesterol checked. Ask your health care team how often you need a cholesterol test. Lifestyle changes and medicines may be recommended to control high cholesterol.
• Limit alcohol. Binge drinking (having five drinks in two hours for men or four drinks for women) can increase the risk of atrial fibrillation. In some people, even lower amounts of alcohol can trigger AFib.
• Practice good sleep habits. Poor sleep may increase the risk of heart disease and other chronic conditions. Adults should aim to get 7 to 9 hours of sleep daily.

It's also important to have regular health checkups. Tell your health care team if your AFib symptoms get worse.

If you have an irregular or pounding heartbeat, make an appointment for a health checkup. If AFib is found early, treatment may be easier, and it may work better. You may be referred to a doctor trained in heart diseases. This type of provider is called a cardiologist.

Here's some information to help you prepare for your appointment.

What you can do

• Be aware of any pre-appointment restrictions. When you make the appointment, ask if there's anything you need to do in advance, such as restrict your diet. For example, you may be told not to eat or drink for a few hours before a cholesterol test.
• Write down any symptoms you're having, including any that may seem unrelated to atrial fibrillation. Note when they started, and what you were doing when they started.
• Write down important personal information, including any family history of heart disease, stroke, high blood pressure or diabetes, and any major stresses or recent life changes.
• Make a list of all medicines, vitamins or supplements that you're taking — even those bought without a prescription. Include the dosages.
• Take someone along, if possible. Someone who goes with you can help you remember information you're given.
• Write down questions to ask your health care team.

For atrial fibrillation, some basic questions to ask your doctor include:

• What is likely causing my symptoms or condition?
• What are other possible causes for my symptoms or condition?
• What kinds of tests will I need?
• What's the most appropriate treatment?
• Is there a generic alternative to the medicine you're prescribing?
• What are other treatment options?
• What foods should I eat or avoid?
• What's an appropriate level of physical activity?
• Are there any other restrictions that I need to follow?
• How often should I be screened for heart disease or complications of AFib?
• I have other health conditions. How can I best manage them together?
• Should I see a specialist?
• Are there any brochures or other printed material that I can take home with me? What websites do you recommend visiting?

Don't hesitate to ask any other questions during your appointment.

What to expect from your doctor

During a health checkup, you are usually asked many questions. Being ready to answer them may save time to go over any details you want to spend more time on. You may be asked:

• When did your symptoms start?
• Do you always have symptoms, or do they come and go?
• How severe are your symptoms?
• What, if anything, seems to improve your symptoms?
• What, if anything, appears to worsen your symptoms?

What you can do in the meantime

It's never too early to make heart-healthy lifestyle changes, such as quitting smoking, eating healthy foods and getting more exercise. A healthy lifestyle is the main protection against heart problems and heart-related complications.