How is Atrial Fibrillation Treated?

Currently the primary goals of atrial fibrillation therapy are as follows:

• Restoration of normal sinus rhythm, if possible
• Controlling the rate of ventricular response to atrial fibrillation, assuming sinus rhythm cannot be restored
• Prevention of stroke with blood thinning (anticoagulation) therapy
• Prevention and treatment of complications and side-effects sometimes associated with treatment
• Reducing the risk factors and treating any underlying diseases.

Unfortunately, each of these therapies for atrial fibrillation involves certain potential risks and side effects. Like everything in medical care, you and your doctor will carefully balance the risks of the treatment, the risks of atrial fibrillation, and the benefits of therapy.

Some patients will need medications only for a limited time if a correctable cause for atrial fibrillation is identified and treated. Most individuals, however, will need medication on a regular basis either to control the continuing arrhythmia or to prevent recurrence. Your doctor will choose a medical regimen tailored to your individual needs and your response to the drug. Since your response to any given medicine is difficult to predict, you will very likely need dose adjustments or a switch to another medication depending on your response. All medications have possible side effects and precautionary notes which you will need to discuss with your doctor or pharmacist. Once you have been started on a regimen, you should take your medications exactly as directed. Never change the dose or discontinue them without your doctor's supervision.

There are three types of medications that your doctor will choose from, usually in combinations of at least one from each category.

Medications to slow the heart rate - These medications will not prevent or stop the fibrillation, but will slow the heart rate to a more normal range. The widely used digoxin, usually the initially prescribed medicine, belongs in this category. It is actually one of the oldest medicines known, being derived from the foxglove plant. (Don't try to eat the leaves of that plant: In uncontrolled doses, foxglove can be poisonous!)

Digoxin works well to keep the heart rate down when you are sedentary, but does not help when your heart rate speeds up with exercise or excitement. Another group of medications in this category called beta-blockers, such as metoprolol, propranolol, or atenolol, are commonly used alone or in combination with digoxin to keep the heart rate down during exertion. Calcium channel blockers such as verapamil or diltiazem are also often used in combination therapy for the same purpose. All of these medications work by suppressing the flow of electrical impulses through the AV node, thereby slowing down the rate of ventricular contractions. The name on your pill bottle may differ from these because drugs commonly have a chemical name and a trade name, given by it's manufacturer. For example, "Lanoxin" is a commonly used trade name for digoxin. Ask your pharmacist if you have questions about a specific drug's name.

Medications to stabilize the heart rhythm - These medications are used to restore and maintain the normal sinus rhythm by stabilizing the electrical activity of the heart muscle cells. This process of restoring sinus rhythm with drugs is referred to as chemical cardioversion. With this method, conversion back into normal sinus rhythm is achieved in about 50% of patients. Some of most commonly used drugs include quinidine, procainamide, flecainide, disopyramide, propafenone, amiodarone, and sotalol. Some drugs are taken as pills, others such as ibutilide, are given intravenously. Amiodarone and sotalol also help to slow the heart rate. Many of these drugs are known to cause serious and life-threatening heart rhythm disturbances in the susceptible individuals with other cardiac problems. As a precaution, your doctor may wish to begin treatment with one of these drugs in the hospital for close monitoring.

Medications to "thin" the blood - These medications are intended to reduce your risk of blood clot formation and stroke (anticoagulation therapy). If you are a diabetic, have high blood pressure, or have an enlarged heart, your risk of stroke with atrial fibrillation is particularly high. For those over 65 years of age, anticoagulation therapy using a medicine called warfarin has become the customary treatment for prevention of stroke. This therapy does not completely eliminate your risk, but will reduce it by over 50%. Patients taking this drug must be closely monitored with regular blood tests to continuously assess the amount of blood thinning. A level too low would keep you at risk for developing clots, and a level too high will put you at risk for bleeding. The blood pressure must also be kept under control. Taking extra precautions in the activities of daily living (shaving, playing contact sports, etc.) is another adjustment that you will need to make in your life, due to the increased risk of bleeding. The benefit of using warfarin to prevent blood clot formation needs to be balanced against the bleeding risks if you have high blood pressure, are elderly or unsteady with a history of falling, which can result in serious bleeding. Your doctor may choose to treat you with aspirin therapy instead, a milder form of blood thinner. It may not, however, be as effective as warfarin in the prevention of embolic strokes. You will need to consult your physician or pharmacist regarding the use of analgesics other than aspirin when you are on anticoagulation therapy. There is debate on the treatment of choice for younger patients with "lone" atrial fibrillation, but we often recommend one aspirin a day, just to be on the safe side.