Atrial Fibrillation and Heart Disease
Less Common Causes of Atrial Fibrillation
Less common causes of atrial fibrillation include:
- Hyperthyroidism (overactive thyroid)
- Pericarditis (inflammation of the outside lining of the heart)
- Viral infection
In at least 10% of people with AF, no underlying heart disease is found. In many of these people, AF may be related to alcohol or excessive caffeine use, stress, certain drugs, electrolyte or metabolic imbalances, or severe infections. In some people, no cause can be found.
The risk of AF increases with age, particularly after age 60. According to the CDC, AF affects roughly one in every 10 people ages 80 or older.
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 a blood 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 five to seven 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 -- such as the kidney, heart, or intestines -- also causing problems.
AF can also decrease the heart's pumping ability by as much as 20%-25%. AF combined with a fast heart rate over a period of days to months can result in heart failure. Control of AF can then improve heart failure.
How Is Atrial Fibrillation Diagnosed?
Four tests are used to diagnose atrial fibrillation, including:
- Holter monitor
- Portable event monitor (also called a loop recorder)
- 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.
How Is Atrial Fibrillation Treated?
Many options are available to treat AF, including medication, lifestyle changes, certain medical procedures, and surgery. The choice of treatment for you is based on your heart rate and symptoms. The goals of AF treatment are to:
- Regain normal heart rhythm (sinus rhythm)
- Control the heart rate
- Prevent blood clots
- Reduce the risk of stroke
How Are Medications Used to Treat Atrial Fibrillation?
Medications are prescribed 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 condition by slowing down the heart rate. In both cases, your doctor will give you drugs called anticoagulants to decrease blood clot formation.
- Restore normal heart rhythm. These drugs help return the heart to normal rhythm and maintain that rhythm.
- Many drugs are available to restore and maintain a normal heart rhythm, including: Pronestyl (procainamide); Norpace (disopyramide phosphate); Tambocor (flecainide acetate); Rythmol (propafenone); Betapace (sotalol); Tikosyn (dofetilide); and Cordarone (amiodarone).You may have to stay in the hospital when you first start taking 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. You may need to try several medications so your doctor can find the best one for you.
- Some rhythm control drugs may actually cause more arrhythmias, so it is important to discuss symptoms and any changes in your condition with your doctor.
- The FDA wants patients to be aware that a clinical trial of Multaq (dronedarone), called PALLAS, was halted when the drug doubled the risk of death, stroke, and heart failure hospitalization in heart patients with permanent atrial fibrillation.
- Heart rate control. Heart rate control drugs, such as Lanoxin (digoxin), Toprol, Lopressor (metoprolol), beta-blockers, and calcium channel blockers, are used to help slow the heart rate during atrial fibrillation. You may need to take two different medications to keep your heart rate controlled.
- Blood thinners or anticoagulation drugs. Anticoagulant drugs -- such as Coumadin (warfarin), Xarelto (rivaroxaban), Eliquis (apixaban), and Pradaxa (dabigatran) -- or antiplatelet drugs -- for example, aspirin, Effient, and Plavix (clopidogrel) -- reduce the risk of blood clots and stroke. Although anticoagulant or antiplatelet drugs reduce the risk of stroke, they do not eliminate the risk. Regular blood tests are required when taking Coumadin to evaluate the effectiveness and minimize the risks of the drug. Talk to your doctor about the anticoagulant drug that is right for you.