Prevention

Atrial Fibrillation and Its Treatments

Treatment for atrial fibrillation always includes drugs (aspirin or warfarin) to prevent clots from forming. In addition to anticoagulants (blood thinners), other approaches may include:

• Restoring or maintaining normal heart rhythm. This is accomplished with anti-arrhythmic drug, cardioversion procedures, or surgery to remove the defective area.
• Controlling heart rate. Specific drugs are used for this approach.

Important studies report that controlling heart rate may be the preferable approach. In several studies, rhythm control offered no survival advantages and did not protect against ischemic stroke. Therapies aimed at controlling heart rate, furthermore, had fewer complications.

Drugs to Prevent Blood Clots

After a diagnosis of atrial fibrillation, warfarin (an anticoagulant) or aspirin (an antiplatelet) are essential to prevent blood clots. These drugs can reduce the risk for stroke by over 60% in patients with atrial fibrillation.

• Warfarin (Coumadin) is the main anticoagulant drug used to prevent strokes in high-risk patients with atrial fibrillation. Warfarin carries a risk for bleeding, but for most patients, warfarin’s benefits far outweigh its risks. Patients who are at risk for bleeding usually have a history of alcohol abuse, chronic kidney disease, or previous gastrointestinal bleeding.
• Aspirin is less effective than warfarin, but has a lower risk for bleeding. It is the preferred treatment for younger people with atrial fibrillation and for people who do not have other risk factors for stroke such as high blood pressure or diabetes. Aspirin is also prescribed for higher risk patients who cannot tolerate anticoagulation therapy.
• Researchers are investigating other drugs for preventing stroke and heart problems in patients with atrial fibrillation. These drugs include the antiplatelet medication clopidogrel (Plavix) and the angiotensin receptor blocker irbesartan (Avapro). Recent research indicates that anticoagulants such as warfarin (Coumadin) work better for atrial fibrillation patients than the combination of clopidogrel plus aspirin. Clinical trials are continuing to investigate whether clopidogrel alone is better than aspirin alone.

Restoring and Controlling Heart Rhythm

To initially restore heart rhythm, anti-arrhythmic drugs are usually tried first. If they fail to restore normal rhythm, cardioversion is often effective. (Some experts suggest trying cardioversion first to avoid side effects of the drugs.) Long-term maintenance therapy using anti-arrhythmic drugs may be required.

Electrical Cardioversion. Electrical cardioversion is mild shock therapy and is the current standard treatment used to restore normal heart rhythm. It is conducted as follows:

• Anticoagulants (drugs used to prevent blood clotting) should be administered, if possible, at least 3 weeks before the procedure.
• During the procedure, the patient must be conscious and, although sedated, can experience some pain from the procedure.

Although the stabilizing effect is usually only temporary, some evidence suggests that a series of cardioversion may succeed in maintaining normal rhythm in young healthy patients without the need for antiarrhythmic medications.

Low-energy implanted cardioverters (Atrioverter, Jewel AF) are being investigated for maintenance. Studies are promising.

Drugs Used for Maintaining Normal Heart Rhythm. For maintaining a stable rhythm, the following drugs may be used. The specific choices typically depend on whether the patient has existing heart disease or not:

• For patients with no heart disease, the first choices include sotalol, flecainide, or propafenone, which are often used sequentially. If these fail, then amiodarone or a newer drug dofetilide (Tikosyn) may be tried. Others include ibutilide (Covert) and azimilide. If these drugs are not effective, other drugs tried include quinidine, procainamide, and disopyramide.
• In patients with heart disease, amiodarone, dofetilide, or sotalol are commonly used depending on the cause of heart disease.

Amiodarone is more effective than most others and has been thought to be safer than many other similar drugs. Even in low doses, however, there is a high incidence of side effects, including thyroid disorders, neurologic, skin, and eye problems, and abnormally slow heart beats. Many of these drugs carry a small but significant increased risk, however, for a life-threatening arrhythmia called torsades de pointes. People with certain heart conditions should avoid these drugs.

Surgical Procedures for Complex AF. In some difficult cases, surgery may be recommended. The options and candidates depend on other complicating factors. The following are some examples:

• AV node ablation involves severing the communication between the atria (the two upper chambers of the heart) and the ventricles (the two lower chambers). A pacemaker is then implanted just under the skin with electrodes leading to the ventricles. This approach is very effective, but it is irreversible and lifelong. Radiofrequency ablation may be an option in some patients.
• A more aggressive procedure uses open chest surgery, in which a maze of cuts is made in the atria. As they heal, the scar tissue prevents the heart circuitry from misfiring. This technique controls atrial fibrillation in more than 90% of appropriate candidates. A new procedure is similar but less invasive.

Controlling Heart Rate

Drugs Used to Control Heart Rate. Beta-blockers or calcium channel blockers are used to control heart rate at the onset of atrial fibrillation. Digitalis, an older drug, is not used as often but can be effective in combination with the other drugs.