Atrial Fibrillation and Its Treatments

The object of treatment for Atrial Fibrillation is to prevent blood clots from forming by first restoring and then maintaining normal heart rhythm and function. To initially restore heart rhythm, anti-arrhythmic drugs are usually used first. If they fail to restore normal rhythm, a procedure known as cardioversion is often effective. Even if a steady rhythm is restored by drugs or cardioversion, however, it often cannot be sustained for prolonged periods, so long-term maintenance therapy using anti-arrhythmic drugs may be required.

Anti-Clotting Drugs. After a diagnosis of Atrial Fibrillation, patients usually need to take drugs to reduce blood clotting, usually warfarin (an anticoagulant) or aspirin.

     
  • Warfarin (Coumadin, Panwarfin) is an anticoagulant and is especially effective in preventing strokes in this population. Anti-coagulant agents reduce the risk for stroke by 62%, and are the agents of choice in preventing first and second strokes in high-risk patients with Atrial Fibrillation. Warfarin carries a risk for bleeding, however, and requires careful monitoring. Those at particular risk for bleeding are patients with a history of alcohol abuse, chronic kidney disease, or previous gastrointestinal bleeding. In one study, elderly women were half as likely to receive warfarin than men were, most likely because they are at higher risk for bleeding than men are. Nevertheless, this agent is still the best choice for women as well as men in this patient group.  
  • Aspirin is less effective but also has a lower risk for bleeding. It is used by people who cannot tolerate anticoagulation therapy. It is currently the preferred treatment for younger patients and those with no other medical risk factors for stroke.

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 three 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 cardioversions may succeed in maintaining normal rhythm in young healthy patients without the need for antiarrhythmic medications.

Implanted cardioverters (eg, Atrioverter, Jewel AF) are being investigated for maintenance. Studies are very promising.

Drugs used to Restore Normal Rhythm . Before any antiarrhythmic agent is used, conditions that might be causing the Atrial Fibrillation should be addressed first. In some cases, medications rather than electric cardioversion may be used for restoring normal rhythm.

They include intravenous beta-blockers (such as propranolol) or calcium channel blockers. Digitalis, an older drug, is not used as often but is proving to be very effective in combination with a beta-blocker. These agents are used to reduce heart rate at the onset of Atrial Fibrillation. None of them, however, are able to convert an abnormal heart rhythm to a normal one and are not useful for rhythm maintenance.

Drugs Used for Maintaining Normal Heart Rhythm. For maintaining a stable rhythm, the following drugs may 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 are flecainide, propafenone, or sotalol. If these fail, then amiodarone or a newer agent dofetilide (Tikosyn) may be tried. Dofetilide is a class III agent. Others include ibutilide (Covert), and azimilide. If these agents are not effective, than other drugs tried include quinidine, procainamide, and disopyramide.  
  • In patients with heart disease, amiodarone, dofetilide, or sotadol are commonly used depending on the cause of heart disease. It is very effective 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 and so should be avoided by people with certain heart conditions.

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 must be used life-long. 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. It controls Atrial Fibrillation in more than 90% of appropriate candidates. A new procedure is similar but less invasive.

Provided by ArmMed Media
Revision date: June 14, 2011
Last revised: by David A. Scott, M.D.