Of the two general approaches used to treat atrial fibrillation, rhythm control is the one that initially seems more desirable. This approach attempts to restore and maintain a normal heart rhythm. While this is clearly the better treatment approach for many people with atrial fibrillation, it can carry substantial risk and is often not completely effective. It is not right for everyone.
The rhythm-control approach has two general steps: restoring and then maintaining a normal heart rhythm.
Restoring a Normal Heart RhythmIf you are in atrial fibrillation, your doctor can attempt to restore your normal heart rhythm by using antiarrhythmic drugs or electrical cardioversion.
Several antiarrhythmic drugs can be given intravenously in an attempt to stop the atrial fibrillation and restore a normal rhythm. These include flecainide (Tambocor), ibutilide (Corvert), propafenone (Rhythmol) and dofetilide (Tikosyn). However, these drugs will successfully restore a normal rhythm only 50 percent to 60 percent of the time, and there can be side effects.
Most cardiologists prefer electrical cardioversion instead. With electrical cardioversion, you will be placed in a light anesthesia-induced sleep for a few minutes. The doctor will administer an electrical discharge to your chest via a set of paddles. This procedure is painless, quick, safe and effective.
The major complication of cardioversion has to do with the atrial fibrillation rather than with the procedure. After atrial fibrillation has been present for more than 24 to 48 hours, blood clots can begin forming in the atria. When the atria begin contracting again (because atrial fibrillation has now been stopped), the action of the beating atria can dislodge these fresh clots from the heart and cause a stroke. The risk of having a stroke after cardioversion is greatly reduced by performing the procedure within 24 hours of the onset of the arrhythmia or by giving an anticoagulant drug (blood thinner), such as Coumadin, for four to six weeks before cardioversion.
Another alternative to preventing post-cardioversion strokes is to perform a transesophageal echocardiogram to look for clots in the atria. If none is seen, it is relatively safe to proceed with cardioversion without taking the step of anticoagulating for a month or longer.
This first step to rhythm control - restoring a normal heart rhythm - is successful more than 98% of the time.
Maintaining a Normal RhythmThe real trick to rhythm control is maintaining a normal heart rhythm once it has been restored.
Typically, with the first episode of atrial fibrillation, most doctors will simply restore a normal rhythm and send the patient home. Many people will maintain a normal rhythm for months or even years. This favorable result is especially likely if this was the first episode of atrial fibrillation or if the arrhythmia was produced by a readily reversible underlying cause, which has since been treated.
However, sooner or later the atrial fibrillation is likely to recur. When that happens the "maintenance" phase of the rhythm control method becomes much more complicated.
Most typically, once normal rhythm is restored the doctor will recommend an antiarrhythmic drug to help maintain that normal rhythm. Antiarrhythmic drugs, aside from being among the most toxic drugs used in medicine, are only moderately effective at keeping the atrial fibrillation from coming back. Consequently, two or more "trials" of these drugs are often required, looking for a drug that both maintains a normal rhythm and is sufficiently tolerated.
Even with a painstaking trial-and-error approach, an antiarrhythmic drug that achieves good control of the atrial fibrillation without causing intolerable side effects will be found only about half the time.
This kind of success rate with antiarrhythmic drugs obviously leaves much to be desired. For this reason, doctors and researchers have been hard at work for more than a decade to develop safe and effective methods to "cure" atrial fibrillation - that is, to maintain a normal heart rhythm permanently - using ablation procedures. While a lot of progress has been made, ablation procedures for curing atrial fibrillation are still only partially effective and still carry a substantial risk of serious complications. Ablation is a good option for some patients with atrial fibrillation, but it is not for everybody.
SummaryIf the rhythm-control approach for treating atrial fibrillation were always safe and effective, then it would be used in everyone who has this arrhythmia. Unfortunately, while rhythm control is clearly the best approach for many people, it leaves much to be desired. This is why the alternative approach - rate control - is used instead in so many patients. And this is why you need to learn as much as you can about all the alternatives before you decide on the right atrial fibrillation treatment for you.
Fuster, V, Ryden, LE, Cannom, DS, et al. ACC/AHA/ESC 2006 Guidelines for the Management of Patients With Atrial Fibrillation A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and the European Society of Cardiology Committee for Practice Guidelines (Writing Committee to Revise the 2001 Guidelines for the Management of Patients With Atrial Fibrillation). J Am Coll Cardiol 2006; 48:e149.