Q. What Is Atrial Fibrillation?
Atrial fibrillation (AF) is the most common type of irregular heartbeat. If you have AF, the impulse does not travel in an orderly fashion through the atria. Instead, many impulses begin and spread through the atria and compete for a chance to travel through the AV node. The impulses originate from tissues other than the heart's electrical system.
The firing of these impulses results in a very rapid and disorganized heartbeat. The rate of impulses through the atria can range from 300 to 600 beats per minute. Luckily, the AV node limits the number of impulses it allows to travel to the ventricles. As a result, the pulse rate is often less than 150 beats per minute, but this is often fast enough to cause symptoms.
Q. What Are the Symptoms of Atrial Fibrillation?
Most people with AF experience one or more of the following symptoms:
- Heart palpitations (a sudden pounding, fluttering, or racing feeling in the heart).
- Lack of energy; tired.
- Dizziness (feeling faint or light-headed).
- Chest discomfort (pain, pressure, or discomfort in the chest).
- Shortness of breath (difficulty breathing during activities of daily living).
Q. What Causes Atrial Fibrillation?
Atrial fibrillation is associated with many conditions, including:
- High blood pressure.
- Coronary artery disease (hardening of the heart arteries).
- Having undergoing heart surgery.
- Chronic lung disease.
- Heart failure.
- Cardiomyopathy (disease of heart muscle that causes heart failure).
- Congenital (present at birth) heart disease.
- Pulmonary embolism (blood clot in lungs).
- Hyperthyroidism (overactive thyroid, uncommon).
- Pericarditis (inflammation of the outside lining of the heart, uncommon).
- In at least 10% of people with AF, no underlying heart disease is found. In these people, AF may be related to alcohol or excessive caffeine use, stress, certain drugs, metabolic imbalances or severe infections. In some people, no identifiable cause can be found.
- The risk of AF increases with age, particularly after 60 years of age.
Q. Why Is Atrial Fibrillation Dangerous?
Many people live for years with atrial fibrillation without problems. However, because the atria are beating rapidly and irregularly, blood does not flow through them as quickly. This makes the blood more likely to clot. If the clot is pumped out of the heart, it can travel to the brain, resulting in a stroke. The likelihood of a stroke in people with AF is 5 times higher than in the general population. Although about half of all blood clots related to AF result in stroke, clots can travel to other parts of the body (kidney, heart, intestines) causing problems.
AF can also decrease the heart's pumping ability by as much as 20%-30%. AF combined with a fast heart rate over a long period of time, can result in heart failure.
Q. How Is Atrial Fibrillation Diagnosed?
Four tests are used to diagnose atrial fibrillation, including:
- Holter monitor
- Event monitor
- Transtelephonic monitor
These monitoring devices help your doctor learn if you are having irregular heartbeats, what kind they are, how long they last, and what may be causing them.
Q. How Are Medications Used to Treat Atrial Fibrillation?
Medications are prescribed in the management of AF depending on the overall treatment goal. If the goal is to restore normal heart rhythm, a type of drug called an antiarrhythmic is prescribed. If it's not possible to achieve this goal, doctors will try to manage your disease by slowing down the heart rate. In both cases, your doctor will give you medications called anticoagulants to decrease blood clot formation.
Restore normal heart rhythm. Many medications are available to restore and maintain a normal heart rhythm, including Quinidex (quinidine), Pronestyl (procainimide), Norpace (disopyramine), Toprol, Lopressor, Tambocor, Rythmol (propafenone), Betapace (sotalol), Tikosyn, and Cordarone. You may have to stay in the hospital when you first start using these drugs so that your heart rhythm can be carefully monitored. These medications are effective 30%-60% of the time, but may lose their effectiveness over time. Many have potentially serious side effects, so you may need to try several medications to find the best one for you.
Heart rate control. Control of the heart rate can be obtained using Lanoxin (digoxin), or two other groups of medications that lower heart rate, called beta-blockers, and calcium channel blockers.
Blood thinners or anticoagulation drugs. Coumadin (warfarin) reduces the risk of stroke by 60%-80% in people with AF. When Coumadin is used, regular blood tests are required to assure that the blood is thinned at a safe and effective level. Some people may be treated with aspirin instead of Coumadin.
When medications do not work to correct or control AF, a procedure may be necessary.
Source: WebMd Health
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