Atrial fibrillation

Atrial fibrillation

Atrial fibrillation is an irregular heartbeat in which the upper chambers of the heart (the atria) beat inconsistently and rapidly.

Types of atrial fibrillation

Atrial fibrillation is a type of arrhythmia. There are four main types of atrial fibrillation—paroxysmal, persistent, long-term persistent, and permanent atrial fibrillation. The type of atrial fibrillation that you have depends on how often atrial fibrillation occurs and how it responds to treatment.

* You may experience a brief event—a paroxysm—of atrial fibrillation. It may pass without symptoms, or you may feel it strongly. It usually stops in less than 24 hours but may last up to a week. Paroxysmal atrial fibrillation can happen repeatedly. You may need treatment or your symptoms may go away on their own. When this kind of atrial fibrillation alternates with a heartbeat that is slower than normal, it is called tachybrady syndrome.

Persistent atrial fibrillation

Persistent atrial fibrillation is a condition in which the abnormal heart rhythm lasts for more than a week. It may ultimately stop on its own but probably will need treatment.

Long term persistent atrial fibrillation

With this condition, the abnormal heart rhythms last for more than a year without going away.

Permanent atrial fibrillation

Sometimes atrial fibrillation does not get better, even when you have tried several times to restore a normal heart rhythm with other medicines or other treatments. At this point, your atrial fibrillation is considered permanent.

Cause of atrial fibrillation

Atrial fibrillation heart

Changes to the heart’s tissue and to its electrical signals most often cause atrial fibrillation. To understand atrial fibrillation, it helps to know how the heart works. When the heart’s tissue or signaling is damaged, the regular pumping of the heart muscle becomes fast and irregular. Most often, damage to the heart is the result of other conditions such as high blood pressure and ischemic heart disease. Other factors can also raise your risk of atrial fibrillation.

Changes to the heart tissue

Usually the cells of the heart fire and contract together. However, when aging, heart disease, infection, genetics, or other factors change heart tissue, that pattern breaks down. This can happen because of fibrosis, inflammation, a thinning or thickening of the heart walls, lack of blood flow to the heart, or an abnormal buildup of proteins, cells, or minerals in heart tissue.

Changes in the electrical signal to the heart

Usually, a trigger heartbeat sets off atrial fibrillation. Electrical signals from this trigger may then cause the heart to beat slower or faster than usual because of changes in heart tissue. Sometimes, the signals create an atypical loop, telling the heart to contract over and over. This can create the fast, chaotic beating that defines atrial fibrillation.

Variations in the heart’s electrical signaling can be due to differences in heart anatomy, premature or extra heartbeats, normal heart rate adjustments, patches of faster or slower tissue, and repeated stimulation of certain tissue patches.

Facts about Atrial fibrillation

In the United States:

• An estimated 2.7–6.1 million people in the United States have AFib. With the aging of the U.S. population, this number is expected to increase.
• Approximately 2% of people younger than age 65 have AFib, while about 9% of people aged 65 years or older have AFib.
• African Americans are less likely than those of European descent to have AFib.
• Because AFib cases increase with age and women generally live longer than men, more women than men experience AFib.

Costs and consequences

According to the CDC, >750,000 hospitalizations occur each year because of AFib in the United States. The condition contributes to an estimated 130,000 deaths each year. The death rate from AFib as the primary or a contributing cause of death has been rising for more than two decades.

AFib costs the United States about $6 billion each year. Medical costs for people who have AFib are about $8,705 higher per year than for people who do not have AFib

Risk factors for atrial fibrillation

• Age - The risk of atrial fibrillation increases as you age, especially after age 65. Atrial fibrillation is rare in children, but it does occur, especially in boys and in children who have obesity.
• Family history and genetics - If someone in your family has had atrial fibrillation, you have a higher risk of developing atrial fibrillation, too. Scientists have found some genes with mutationsthat raise the risk of atrial fibrillation. Some of these genes influence fetal organ development or heart cell ion channels. Sometimes these genetic patterns are also linked to heart disease. Some genetic factors may raise the risk of atrial fibrillation in combination with such factors as age, weight, or sex.
• Lifestyle habits - Some lifestyle habits can raise or lower your risk of atrial fibrillation, including the following:
  • Alcohol. Drinking large amounts of alcohol, especially binge drinking, raises your risk of atrial fibrillation. Even modest amounts of alcohol can trigger atrial fibrillation in some people.
  • Illegal drugs. Some street drugs, such as cocaine, can trigger atrial fibrillation or make it worse.
  • Physical activity. Some competitive athletes and people—men, in particular—participating in endurance sports or exerting themselves at work may have a higher risk of atrial fibrillation. At the same time, moderate physical activity can have a protective effect. Physical fitness appears to be linked to a lower risk of atrial fibrillation.
  • Smoking. Studies have found that smoking increases the risk of atrial fibrillation. The risk appears to be higher the longer you smoke and decreases if you quit. Exposure to secondhand smoke, even in the womb, can increase a child’s risk of developing atrial fibrillation.
  • Stress. Stressful situations, panic disorders, and other types of emotional stress may be linked to a higher risk of atrial fibrillation.
• Other medical conditions - Many other medical conditions can increase your risk of atrial fibrillation, especially heart problems. As you age, having more than one condition may increase your risk. Conditions that raise the risk of atrial fibrillation include:
  • Chronic kidney disease
  • Conduction disorders
  • Congenital heart defect
  • Diabetes
  • Heart attack
  • Heart failure
  • Heart inflammation
  • Heart tissue that is too thick or stiff
  • Heart valve disease
  • High blood pressure
  • Hyperthyroidism, an overactive thyroid gland
  • Ischemic heart disease
  • Lung diseases, including COPD
  • Obesity
  • Sarcoidosis
  • Sleep apnea
  • Venous thromboembolism
• Race or ethnicity - In the United States, atrial fibrillation is more common among whites than among African Americans, Hispanic Americans, or Asian Americans. Although people of European ancestry are more likely to develop the condition, African Americans with atrial fibrillation are more likely to have complications such as stroke, heart failure, or ischemic heart disease.
• Surgery - You may be at risk for atrial fibrillation in the early days and weeks after surgery of the heart, lungs, or esophagus. Surgery to correct a congenital heart defect can also raise the risk of atrial fibrillation. This can happen years after a childhood surgery or when you have surgery as an adult to correct a lifelong condition.

Screening for atrial fibrillation

Typically doctors screen for atrial fibrillation only when you have symptoms. However, your doctor may check for signs of atrial fibrillation as part of your regular medical care. Screening tests include checking your pulse or recording your heart’s electrical activity. Your doctor may recommend healthy lifestyle changes to help you lower your risk of developing atrial fibrillation.

Screening may be part of your regular care if you are 65 or older or if you have other risk factors.

• Your doctor may check your pulse. Even without symptoms, your heart may have an irregular speed or faulty rhythm that your doctor can detect.
• If you have had a stroke and there is no clear cause, your doctor may recommend screening for atrial fibrillation with a Holter or event monitor.
• Several devices are now available to detect and record your heart’s rhythm similar to an electrocardiogram (EKG). These devices may also email the data to your doctor.

To help you lower your risk of atrial fibrillation, your doctor may recommend certain heart-healthy lifestyle changes, including aiming for a healthy weight, being physically active, controlling your blood sugar, limiting alcohol, lowering your blood pressure, managing stress, and quitting smoking.

In addition, some illegal drugs, such as cocaine, can trigger atrial fibrillation or make it worse. Ask your doctor for help avoiding these triggers to prevent arrhythmia.

If you are having heart surgery, your medical team will monitor you. To prevent arrhythmia, your doctor may recommend antiarrhythmic medicine or treatment to maintain or supplement electrolyte levels during or after the procedure.

Prevention of atrial fibrillation

To help prevent a repeat episode of atrial fibrillation, your doctor may recommend the following:

• Medicine that you can take at home as needed to correct your heart rhythm. Before giving you this medicine, the doctor will ask you to take a dose and try to trigger an event to see if the medicine prevents it effectively. You can take this medicine if you start feeling symptoms of atrial fibrillation.
• Treatment for an underlying condition, such as sleep apnea, high blood pressure, and diabetes.
• Heart-healthy lifestyle changes, including aiming for a healthy weight. Combining weight loss with physical activity and the management of other risk factors, such as high blood pressure, diabetes, alcohol use, and smoking, can improve symptoms more than weight loss alone.

Signs and symptoms of atrial fibrillation

The most common symptom of atrial fibrillation is fatigue. Other signs and symptoms include:

• Heart palpitations
• Difficulty breathing, especially when lying down
• Chest pain
• Hypotension, or low blood pressure
• Dizziness or fainting

Keep track of when and how often your symptoms occur, what you feel, and whether these things change over time. They are all important clues for your doctor.

Diagnosis of atrial fibrillation

A doctor will diagnose atrial fibrillation based on your medical and family history, a physical exam, the results from an electrocardiogram (EKG), and possibly other tests and procedures. If you have atrial fibrillation, your doctor will also look for any disease that may be causing it and assess your risk of developing dangerous blood clots. This will help him or her plan the best way to treat you.

Your doctor will do a complete examination of your heart and lungs, including:

• Checking for signs of too much thyroid hormone, such as a thyroid gland that is larger than normal
• Checking for swelling in your legs or feet, which could be a sign of heart failure or a heart that is larger than normal
• Checking your pulse to find out how fast your heart is beating
• Listening to the rhythm of your heartbeat
• Listening to your lungs to check for signs of heart failure or infection
• Measuring your blood pressure

Diagnostic tests for atrial fibrillation

To diagnose atrial fibrillation, your doctor will likely do an EKG first to record your heart’s electrical activity. If the diagnosis is unclear from the EKG or your doctor would like more information, your doctor may order additional testing:

• Blood tests to check the level of substances in the blood such as potassium and thyroid hormone.
• Echocardiography to show areas of poor blood flow to the heart, areas of heart muscle that are not contracting normally, and previous injury to the heart muscle caused by poor blood flow. It may also identify harmful blood clots in the heart’s chambers.

Other tests

• Your doctor may order other tests to record abnormal heart rhythms that happen under specific conditions or outside of the clinic, confirm whether you have atrial fibrillation or another arrhythmia, and figure out which treatment is best. These tests may include:
  • Chest X-ray to look for signs of complications from atrial fibrillation, such as fluid buildup in the lungs or a heart that is larger than normal.
  • Electrophysiology study (EPS) to record your heart’s electrical signals if your doctor wants more detail about what is causing a particular EKG reading or to distinguish among possible types of arrhythmias.
  • Holter and event monitors to record your heart’s electrical activity over long periods of time while you do normal, day-to-day activities. These portable EKG monitors can help assess the cause of symptoms, like palpitations or feeling dizzy, that happen outside the doctor’s office. Most portable monitors will send data directly to your doctor.
  • Loop recorder to record the heart’s electrical activity. Some loop recorder models are worn externally and some require minor surgery to place the device under the skin in the chest area. Implanted devices can record data for months and are used to detect patterns in abnormal heart rhythms that do not happen very often.
  • Sleep study to see if sleep apnea is causing your symptoms.
  • Stress test or exercise stress test to look at changes in your heart’s activity that occur with increase in heart rate, and recovery after exercise. If you cannot exercise, you may be given medicine to make your heart work hard and beat fast.
  • Transesophageal echocardiography (TEE) to detect blood clots that may be forming in the heart’s upper chambers because of atrial fibrillation. It uses sound waves to take pictures of your heart through the esophagus.
  • Walking test to measure your heart activity while you walk for six minutes. This can help determine how well your body can control your heart rate under normal circumstances.

Treatment of atrial fibrillation

Atrial fibrillation is treated with lifestyle changes, medicines, procedures, and surgery to help prevent blood clots, slow your heart beat, or restore your heart’s normal rhythm.

Your doctor may also treat you for an underlying disorder that is causing or raising the risk of atrial fibrillation, such as sleep apnea or an overactive thyroid gland.

Lifestyle changes

Your doctor may recommend adopting heart-healthy lifestyle changes, such as the following:

• Heart-healthy eating patterns such as the DASH eating plan, which reduces salt intake to help lower blood pressure
• Being physically active
• Getting help if you are trying to stop using street drugs
• Limiting or avoiding alcohol or other stimulants that may increase your heart rate
• Managing stress
• Quitting smoking.

Medications

Your doctor may consider treating your atrial fibrillation with medicines to slow your heart rate or to make your heart’s rhythm more even:

• Beta blockers, such as metoprolol, carvedilol, and atenolol, to help slow the rate at which the heart’s lower chambers pump blood throughout the body. Rate control is important because it allows the ventricles enough time to fill with blood completely. With this approach, the abnormal heart rhythm continues, but you may feel better and have fewer symptoms. Beta blockers are usually taken by mouth, but they may be delivered through a tube in an emergency situation. If the dose is too high, it can cause the heart to beat too slowly. These medicines can also make COPD and arrhythmia worse.
• Blood thinners to prevent blood clots and lower the risk of stroke. These medicines include warfarin, dabigatran, heparin, and clopidogrel. You may not need to take blood thinners if you are not at risk of a stroke. Blood-thinning medicines carry a risk of bleeding. Other side effects include indigestion and heart attack.
• Calcium channel blockers to control the rate at which the heart’s lower chambers pump blood throughout the body. They include diltiazem and verapamil.
• Digitalis, or digoxin, to control the rate blood is pumped throughout the body. It should be used with caution, as its use can lead to other arrhythmias.
• Other heart rhythm medicines to slow a heart that is beating too fast or change an abnormal heart rhythm to a normal, steady rhythm. Rhythm control is an approach recommended for people who continue to have symptoms or otherwise are not getting better with rate control medicines. Rhythm control also may be used for people who have only recently started having atrial fibrillation or for highly physically active people and athletes. These medicines may be used alone or in combination with electrical cardioversion. Or your doctor may prescribe some of these medicines for you to take on an as-needed basis when you feel symptoms of atrial fibrillation. Some heart rhythm medicines can make arrhythmia worse. Other side effects include effects on the liver, lung, and other organs, low blood pressure, and indigestion.

Your doctor may recommend treatments for an underlying cause or to reduce atrial fibrillation risk factors. For example, he or she may prescribe medicines to treat an overactive thyroid, lower high blood pressure, or manage high blood cholesterol.

Procedures

Your doctor may recommend a procedure or surgery, especially if lifestyle changes and medicine alone did not improve your symptoms. Typically, your doctor will consider a surgical procedure to treat your atrial fibrillation only if you will be having surgery to treat some other heart condition.

• Catheter ablation to destroy the tissue that is causing the arrhythmia. Ablation is not always successful and in rare cases may lead to serious complications, such as stroke. The risk that atrial fibrillation will reoccur is highest in the first few weeks after the procedure. If this happens, your doctor may repeat the procedure. In some cases, your doctor will place a pacemaker at the time of the procedure to make sure your heart beats correctly once the tissue causing problems is destroyed.
• Electrical cardioversion to restore your heart rhythm using low-energy shocks to your heart. This may be done in an emergency or if medicines have not worked.
• Pacemaker to reduce atrial fibrillation when it is triggered by a slow heartbeat. Typically, a pacemaker is used to treat atrial fibrillation only when it is diagnosed along with another arrhythmia. For example, if you are diagnosed with a slow heart rate or sick sinus syndrome, a pacemaker implanted for that condition can also prevent atrial fibrillation. If you have surgery for a pacemaker, you will need to take blood-thinning medicines.
• Plugging, closing, or cutting off the left atrial appendage to prevent clots from forming in the area and causing a stroke. Your doctor may do this at the same time as surgical ablation. It can be difficult to close off the appendage entirely, and leaking can contribute to ongoing clotting risk.
• Surgical ablation to destroy heart tissue generating faulty electrical signals. The surgeon usually does surgical ablation at the same time as surgery to repair heart valves, but in some cases, surgical ablation can be done on its own.

Complications of Atrial fibrillation

When it is undetected or untreated, atrial fibrillation can lead to serious complications. This is especially significant for African Americans. Even though whites have atrial fibrillation at higher rates, research has found that many of its complications—including stroke, heart disease, and heart failure—are more common among African Americans. Some complications of atrial fibrillation include:

• Blood clots. With atrial fibrillation, the heart may not be able to pump the blood out properly, causing it to pool and form an abnormal blood clot in the heart. A piece of the clot—a type of embolus—can break off and travel through the blood to different parts of the body, blocking blood flow to the brain, lungs, intestine, spleen, or kidneys. Atrial fibrillation may also increase the risk of venous thromboembolism, which is a blood clot that forms in a vein.
• Cognitive impairment and dementia. Some studies suggest that impaired cognition, Alzheimer’s disease, and vascular dementia occur more often among people with atrial fibrillation. This may be due to blockages in the blood vessels of the brain or reduced blood flow to the brain.
• Heart attack. The risk of a heart attack from atrial fibrillation is highest among women and African Americans and especially in the first year after atrial fibrillation is diagnosed.
• Heart failure. Atrial fibrillation raises your risk of heart failure because the heart is beating fast and unevenly. The heart’s chambers do not fill completely with blood and cannot pump enough blood to the lungs and body. Atrial fibrillation may also make your heart failure symptoms worse.
• Stroke. If an embolus travels to the brain, it can cause a stroke. For some people, atrial fibrillation has no symptoms, and a stroke is the first sign of the condition. If you have atrial fibrillation, the risk of a stroke is higher if you are a woman.
• Sudden cardiac arrest. With atrial fibrillation, there is an increased risk that the heart may suddenly and unexpectedly stop beating if you have another serious heart condition.

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