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Atrial Fibrillation Explained
Your heart is a muscle whose job is to pump blood throughout the body at a steady pace. A healthy adult generally has a resting heart rate between 60 to 80 beats per minute, but everyone’s rhythm is unique. Atrial fibrillation, also known as AFib or AF, is a type of irregular heart rhythm (arrhythmia). An arrhythmia is a condition where the heart beats with an abnormal rhythm; the heart beats too fast, too slow, or in an irregular way.
Atrial fibrillation is the most common type of arrhythmia and is caused by disturbances in the electrical signals of the heart. The Centers for Disease Control and Prevention estimate that between 2.7 to 6.1 million Americans have AFib. Atrial fibrillation affects the top two chambers of the heart called the atria, whereas ventricular fibrillation (another kind of arrhythmia) affects the lower chambers of the heart called the ventricles.
In AFib, the heart beats much faster than normal, and the heart's upper and lower chambers do not work as synergistically as they should. The sinus node is an area of specialized cells in the upper right chamber (right atrium) that sends out electrical impulses — this is the heart’s natural pacemaker. AFib arises from abnormal rapid electrical firing in one or more of the four pulmonary veins that return blood from the lungs to the left atrium, which causes the atria to twitch (fibrillate); as this happens, blood is no longer pumped into the ventricles and can lead to the formation of a blood clot. Medications like Metoprolol or Nadolol can be used to control some AFib symptoms.
Watch the video below for a short and concise explanation of AFib.
In this article, we cover the kinds, causes, risk factors, symptoms, and treatment for AFib.
Four Types of Atrial Fibrillation
There are four main types of AFib — paroxysmal, persistent, long-term persistent, and permanent atrial fibrillation.
a. Paroxysmal Atrial Fibrillation
A paroxysm is a brief event or experience of AFib that can happen once or repeatedly. At times it may present no symptoms, and other times you may feel the AFib quite strongly. This event can stop in under 24 hours but may last up to a week. When a paroxysmal AFib alternates with a slower than normal heart rate, called bradycardia, it is called tachybrady syndrome.
b. Persistent AFib
In this type of AFib, the symptoms can last longer than a week, and the heart is unable to regulate it’s rhythm anymore. Persistent AFib can stop on its own but treatment may be necessary.
c. Long-Term Persistent AFib
In long-term persistent AFib, the heart goes in and out of its natural rhythm for more than a year without stopping.
d. Permanent AFib
When AFib persists and does not go away, you may seek treatment. If you have tried many times to restore heart rhythm through medications or other treatments and your AFib does not get better, it is considered permanent.
In a healthy heart, the atria contract at the same time to send blood down to the lower two chambers of the heart, the ventricles. The ventricles also work together by then contracting at the same time to send blood throughout the body. Changes and damage to different heart tissues cause a disruption in the heart’s regular electrical signaling patterns and may cause atrial fibrillation. When the heart’s tissues are damaged, the heart muscle begins to pump too fast and with an irregular beat.
Factors such as aging, heart disease, infection, and genetics can change or damage heart tissue. This damaged heart tissue can be a result of fibrosis, inflammation, a thinning or thickening of the walls inside the heart, lack of blood flow to the heart, or a buildup of cells, minerals, and cells. 
There are several causes of AFib:
- High blood pressure
- Coronary artery disease
- Heart attack
- Coronary artery bypass surgery
- Pericarditis (inflammation of the heart)
- Diseases that damage the valves of the heart
- Hyperthyroidism (overactive thyroid)
- Pulmonary embolism (blood clot in the lung)
- Atrial septic defect (repaired in childhood) and other congenital heart defects
- Heavy alcohol use
- Unhealthy weight
- Sleep apnea
- Age (AFib increases with age)
A risk factor is something that increases risk or susceptibility. There are several different risk factors outlined below that increase your chances of getting AFib.
Increased age presents an AFib risk. Conditions that are risk factors for AFib become more prevalent in an aging population, such as high blood pressure or coronary artery disease. If AFib occurs in a younger individual, it is likely associated with other heart conditions, such as a congenital heart defect.
Family history and genetics
You are at a higher risk for developing AFib if someone in your family previously had this condition. Genetic factors, such as inheritance of certain diseases or a gene mutation, increases the risk for AFib. A genetic predisposition for heart disease, for example, is a risk factor. Age, weight, and sex, in combination with genetics, may influence the onset of AFib.
The following lifestyle habits and choices can either raise or lower the risk of AFib, including:
Alcohol: There is evidence that binge drinking, as well as moderate, consistent alcohol intake, raises one's risk for developing AFib. A study published in 2019 found that frequent drinking (amount of alcohol per week) is a more important risk factor for the onset of AFib than binge drinking (amount consumed per drinking session). There was a two percent increase in the risk for new-onset AFib with every added gram of alcohol consumed each week. 
Illegal drugs: Along with alcohol, illicit drugs are arrhythmogenic — they tend to produce a cardiac arrhythmia or flutter. Illicit drugs such as cocaine, amphetamine, and ecstasy share similar negative effects on the cardiovascular system, which can induce AFib in some people. 
Physical activity: A scientific report published in 2019 describes that meeting the recommended target for physical activity, a minimum of 150 minutes per week, is associated with maximum protection against AFib in the general population. Moderate-intensity exercise is recommended. Elite athletes and some people who participate in endurance sports with very high exertion levels may have an increased risk for AFib. 
Smoking: A 2018 study published in the European Journal of Preventative Cardiology suggests that smoking is associated with an increased risk of AFib. There appears to be a dose-response relationship between the number of cigarettes smoked and the risk of AFib; for every ten cigarettes smoked per day, there is a 14 percent increased risk for AFib. 
Stress: sleep deprivation and fatigue, physical illness, and emotional triggers (such as anxiety, fright, or extreme happiness) all-cause physical stress on the body. Being stressed means an increased likelihood of abnormal electrical activity in the heart.
Several classes of drugs may induce AFib in patients with or without preexisting heart disease. Although prescribed-drug-induced AFib may only play a minor role in patients presenting this condition, it's important to recognize these drugs as a potential cause, especially in the elderly population as age is a known risk factor for the onset of AFib.
Drugs that may induce AFib include:
- Cardiovascular drugs such as cardiac stimulants, antiarrhythmics, diuretics, and cholinergics
- Respiratory system drugs such as sympathicomimetic inhalants, xanthenes, corticosteroids, and cytostatics
- Central nervous system drugs such as (anti)cholinergics, dopamine agonists, antidepressants/antipsychotics, antimigraine drugs, and anesthetics
- Genitourinary system drugs such as drugs for erectile dysfunction and premature labor
- Nicotine 
Other Medical Conditions
Many other medical conditions increase the risk of AFib, including:
- Chronic kidney disease
- Conduction disorders
- Congenital heart defects
- Heart attack and failure
- Heart inflammation
- Heart valve issues such as tissue that is too thick or thin, and heart valve diseases
- High blood pressure
- Coronary heart disease
- Lung diseases (COPD)
- Sleep apnea
- Blood clot (deep vein thrombosis or pulmonary embolism)
Race or Ethnicity
Biracial studies in the US demonstrate lifetime risk percentages for AFib are approximately one-in-three for Caucasians and one-in-five for African Americans. 
In the first few weeks after surgery to the heart, lungs, or esophagus, your risk for AFib increases. Congenital heart defect surgeries also pose a risk for AFib and can happen years after a childhood surgery.
Signs and Symptoms
Atrial fibrillation may or may not present symptoms. Often it can occur out of nowhere or occur occasionally. For others, symptoms of AFib are frequent, especially for those with worsening heart disease. Even if your AFib is undetected, or if you leave it untreated, serious complications can arise, such as stroke and heart failure.
The most common symptoms of AFib include:
- Heart palpitations
- Difficulty breathing (noticeably when lying down)
- Chest pain
- Low blood pressure
- Dizziness or fainting
- Intolerance to exercise
Your doctor is the best person to determine whether or not treatment is necessary for your AFib. Treatment for AFib may involve lifestyle changes, medications, or surgery, determined on an individual basis. Different treatment methods aim to restore the heart's natural rhythm, maintain a steady heart rate or slow the heart rate and prevent the incidence of blood clots.
Lifestyle recommendations may include dietary changes and an increase in physical activity. Reducing alcohol intake and quitting smoking are important lifestyle changes to make to prevent AFib as well. Lastly, stress management is vital to maintain heart health.
If you do require treatment, your doctor may prescribe the following medications:
- Beta-blockers such as Metoprolol or Nadolol— decrease heart rate
- Calcium channel blockers — relax arterial muscles
- Sodium and potassium channel blockers — regulate heart rhythm
- Digitalis glycosides or digoxin — strengthen heart contraction
- Blood thinners — prevent blood clots
- Other heart rhythm medications such as Multaq (Dronedarone)
If your doctor prescribes blood-thinning medications to prevent blood clots, non-vitamin K oral anticoagulants are often preferred, such as rivaroxaban (Xarelto), and apixaban (Eliquis). Always consult your doctor for medications and understand the side-effects of each medicine before taking it.
If lifestyle changes and medicine didn’t seem to improve your AFib symptoms, doctors might recommend specific procedures. Generally, a doctor will consider surgery to treat AFib only if you will also be having surgery to treat another heart condition. 
Procedures to treat AFib include:
- Catheter ablation
- Electrical cardioversion
- Plugging, closing, or cutting off the left atrial appendage
- Surgical ablation
AFib symptoms can cause feelings of anxiety or fear in those who experience them. If you are concerned, learn more about lifestyle changes and treatment options that are available to you. Knowledge is wealth for your health, so it pays to educate and understand your condition to prevent AFib in the future.
The content in this article is intended for informational purposes only. This website does not provide medical advice. In all circumstances, you should always seek the advice of your physician and/or other qualified health professionals(s) for drug, medical condition, or treatment advice. The content provided on this website is not a substitute for professional medical advice, diagnosis or treatment.