Atrial Fibrillation (A-Fib) Quiz: Test Your Medical IQ

Atrial fibrillation (also known as AF, A fib, or A-fib) is the most common, abnormal rhythm of the heart. More specifically, it is an irregular heart rhythm (arrhythmia) that starts in the upper parts (atria) of the heart.

There is not only electricity within the heart, the heart itself has an entire electrical system complete with signals that control the rate and rhythm of each heartbeat. With each beat, an electrical signal is spread from the top of the heart to the bottom. As the signal travels, it causes the heart to contract, which pumps blood.

The heart beats and pumps blood with a regular rhythm. The heart may beat faster or slower with a shorter or longer interval between beats, but at any one rate, the interval between beats is constant. This regular rhythm occurs as a result of regular electrical discharges (currents) that travel through the heart and cause the muscle of the heart to contract. In atrial fibrillation, the electrical discharges are irregular and rapid and, as a result, the heart beats irregularly and, usually, rapidly.

Damage to the electrical system within the heart causes atrial fibrillation. This damage is usually the result of other conditions that affect the general health of the heart such as high blood pressure and coronary heart disease. Inflammation also is thought to play a role in causing atrial fibrillation. Still, sometimes the cause of atrial fibrillation is unknown.

Atrial fibrillation puts a person at risk for stroke.

With atrial fibrillation, heart contractions are more rapid, but weaker than regular heart contractions, resulting in slow blood flow in the atrium. As the blood pools, it becomes sluggish, which can result in the formation of blood clots. Sometimes, these blood clots dislodge, pass through the ventricles, and lodge in the brain, lungs, and other parts of the body. If a blood clot leaves the heart and travels to the brain, it can cause a stroke by blocking the flow of blood through cerebral arteries. In people over 80 years old, atrial fibrillation is the direct cause of 1 in 4 strokes.

There are many risk factors for developing atrial fibrillation. People with the following diseases or conditions have an increased risk for developing atrial fibrillation: coronary heart disease, heart attack, increased or advancing age, high blood pressure, overactive thyroid (hyperthyroidism), mitral valve disease; low amounts of oxygen in the blood, for example, as occurs with lung diseases such as emphysema or chronic obstructive pulmonary disease (COPD); inflammation of the lining surrounding the heart (pericarditis), blood clots in the lung (pulmonary embolism); asthma, excessive alcohol intake, stimulant drug use such as cocaine or decongestants, recent heart or lung surgery, and congenital heart disease.

In some instances atrial fibrillation is easily diagnosed because doctors can hear the rapid and irregular heartbeats using a stethoscope. Also, abnormal heartbeats also can be felt by taking a patient's pulse.

Atrial fibrillation may also be diagnosed through tests including:
- EKG (electrocardiogram): a brief recording of the heart's electrical discharges
- Holter monitor: a continuous recording of the heart's rhythm for 24 hours
- Patient-activated event recorder
- Echocardiography: ultrasound-produced images of the heart's chambers, valves, and lining
- Transesophageal echocardiography (TEE): sound wave-produced heart images
- Chest X-rays
- Exercise treadmill testing

Symptoms of atrial fibrillation can include a feeling like the heart is racing or fluttering in the chest (palpitations); fatigue or weakness; dizziness; chest pain or pressure, and shortness of breath.

Note: Sometimes atrial fibrillation doesn't cause any symptoms, which is why it's important to see your doctor regularly if you're at risk for this condition.

As the risk of atrial fibrillation increases with age, about 1% of people over 60 years of age have atrial fibrillation. The risk of atrial fibrillation increases with age because the risk for heart disease and other conditions that can cause atrial fibrillation also increase with age.

A normal heart beats in a constant rhythm of about 60 to 100 times per minute at rest.

With atrial fibrillation, the firing of impulses that control the normal heartbeat misfire, causing the heart to beat at a rate of 300 to 600 beats per minute.

Atrial fibrillation can also decrease the heart's pumping ability by as much as 20%-25%. Atrial fibrillation combined with a fast heart rate over a period of days to months can result in heart failure.

By medical definition, the term heart failure refers to the inability of the heart to keep up with the demands on it and, specifically, failure of the heart to pump blood with normal efficiency. When this occurs, the heart is unable to provide adequate blood flow to other organs such as the brain, liver, and kidneys. Along with stroke, heart failure is the most common complication of atrial fibrillation.

General treatment options for people with atrial fibrillation include medicines, medical procedures, and lifestyle changes.

To prevent the possibility of clotting and stroke, doctors often prescribe the drug warfarin to thin the blood in AF patients determined to have a high risk of stroke. Individuals on warfarin therapy must be monitored with periodic blood tests to make sure their blood is thin enough to prevent clots, but not so thin as to promote bleeding. Some AF patients have a lower risk of stroke and are treated with aspirin, which reduces clotting but is not as strong as warfarin. Other treatments for AF include medications such as beta blockers or calcium channel blockers to slow the heartbeat, and anti-arrhythmic drugs or electrical cardioversion (which delivers an electrical shock to the heart) to normalize the heartbeat.