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Atrial Fibrillation

OVERVIEW
Atrial fibrillation is an abnormal rhythm of the heart. It is characterized by an irregular and often rapid heartbeat that commonly causes poor blow flow to the body. The heart’s upper two chambers, the left and right atria, beat irregularly due to abnormal electric activity in the heart. There are two forms of atrial fibrillation: intermittent (paroxysmal) atrial fibrillation characterized by episodes of variable frequency and duration and chronic atrial fibrillation which is sustained and does not resolve spontaneously. Because blood is not pumped out of the heart efficiently, it can become static in the heart and form clots, putting patients at significantly increased risk of stroke. Atrial fibrillation can also weaken the heart over time, leading to heart failure.

RISK FACTORS AND CAUSES
The most significant risk factors are aging and previous heart disease, such as hypertension, heart attack, heart failure, heart valve disease, and heart surgery. Atrial fibrillation can also be seen with other medical problems, including alcohol and binge drinking, hyperthyroidism, sleep apnea, chronic lung disease, and certain medications that stimulate the heart (caffeine, theophylline). In some patients, atrial fibrillation can have no apparent cause.

SYMPTOMS
Some patients have no symptoms, while others can have many symptoms, including:
  • Unpleasant palpitations or irregularity of the heart beat
  • Mild chest discomfort (sensation of tightness) or pain
  • A sense of the heart racing
  • Lightheadedness
  • Mild shortness of breath and fatigue that limit the ability to exercise
Some patients report severe symptoms, including:
  • Difficulty breathing
  • Shortness of breath with exertion
  • Fainting, or near fainting, due to a reduction in blood flow to the brain
  • Confusion, due to a reduction in blood supply to the brain
  • Chest discomfort
  • Fatigue


DIAGNOSIS
Atrial fibrillation is diagnosed with an electrocardiogram (ECG or EKG), which records the heart’s electrical activity. Other tests may be performed to rule out associated disorders, such as an echocardiogram (ultrasound) for heart failure and heart valve diseases and blood tests for thyroid disorders. Sleep studies and lung function tests may also be done to uncover sleep apnea or underlying lung disease.

TREATMENT
To treat atrial fibrillation, the heart rate and rhythm must be reset to normal. This process is called cardioversion and can be done with drugs (medical cardioversion) or electricity (electrical cardioversion). Medical cardioversion uses medications called anti-arrhythmics while electrical cardioversion uses paddles or patches placed on your chest to deliver an electric shock. Both procedures are done in the hospital, and electrical cardioversion is performed under sedation so you don’t feel the shock. Because of the significantly increased risk of stroke with atrial fibrillation, many newly diagnosed patients first undergo 3-4 weeks of treatment with a blood thinner (usually warfarin/Coumadin) before cardioversion. An alternative is to undergo a transesophageal echocardiogram, which is a small ultrasound device that is swallowed and lets your doctor look for evidence of clots in your heart. If there are no clots, cardioversion can be performed immediately without delaying 3-4 weeks for blood thinner therapy. Following cardioversion, however, a blood thinner must be taken for at least a month. Most patients require long-term therapy as well, which can be either rhythm control or rate control. In rhythm control, anti-arrhythmic medications are prescribed following cardioversion. The most common of these are Amiodarone (Cordarone, Parcerone), Dronedarone (Maltaq), Propafenone (Rythmol), Sotalol (Betapace), Dofetilide (Tikosyn), and Flecainide (Tambocor). If the rhythm can’t be returned to normal, the goal becomes to slow the heart rate down, or rate control. This can be done through medications (beta blocker, calcium channel blocker, digoxin) or atrioventricular node ablation (destroying abnormally conducting heart cells with radiofrequency energy). Rarely, surgical procedures may need to be used. Some patients may also need treatment to help prevent blood clots for the rest of their lives. These include blood thinners (Warfarin, Dabigatran, Rivaroxiban) and anti-platelet medications, such as aspirin.

PREVENTION
To help prevent spells of atrial fibrillation, you may need to eliminate caffeine and alcohol from your diet. Some over-the-counter (OTC) medications can also trigger episodes as well as interact with anti- arrthythmic medications so it’s important to consult with your doctor before taking any medications. Additionally, it is important to talk to your doctor about how you can treat other conditions you may have that cause atrial fibrillation.

ADDITIONAL INFORMATION
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