Treatment Options for Atrial Fibrillation

Atrial fibrillation (AF)

a chaotic electrical rhythm of the atria
disorganization of atrial electrical activity results in ‘quivering’ rather than contraction
the likelihood of thromboembolism and stroke are increased
rapid atrial electrical activity can be transmitted to the ventricles and produce symptoms of palpitations and dizziness and can decrease ventricular function (tachycardia induced cardiomyopathy)

Treatment strategies must focus on reduction of symptoms and prevention of thromboembolism and tachycardia mediated cardiomyopathy. There are two broad treatment strategies: rate control and rhythm control.

Rate control is designed to reduce the number of impulses conducted to the ventricles. This can be achieved with medications. If medications are ineffective or poorly tolerated rate control can be achieved by catheter ablation of the electrical connection between the atria and the ventricles. Controlling ventricular rates prevents damage to the ventricles and frequently prevents symptoms.
If the rhythm is not maintained in sinus, anticoagulation is necessary to prevent embolism. Because prevention of recurrent AF may not be complete, some physicians recommend anticoagulation despite antiarrhythmic treatment. Anticoagulation with Coumadin to maintain an INR of 2-3 is indicated if any of the following risk factors are present:

Age > 65
Diabetes
Hypertension
Tobacco use
Prior thromboembolism
Decreased LV function
Valvular disease

Patients without any of these risk factors should receive aspirin daily.

Rhythm control treatment is designed to restore and maintain normal rhythm. This can be accomplished either with an antiarrhythmic medication that alters the heart’s electrical properties or with a catheter or surgical ablation procedure.

Antiarrhythmic medications are effective in approximately 60% of patients and even when effective may not completely prevent recurrences. Because antiarrhythmic medications alter the heart’s electrical properties they can have proarrythmic effects leading to ventricular arrhythmia and sudden death.

Ablation: Episodes of AF are frequently initiated by bursts of electrical activity that originate in the pulmonary veins. With the use of percutaneous catheters the pulmonary veins can be electrically disconnected from the atria preventing AF initiation. The success of this procedure depends upon the type of AF present. In paroxysmal AF (episodes terminate spontaneously) success rates are 70-85%. With persistent AF (episodes require electrical cardioversion) success rates are 50-75%. In patients with permanent AF (episodes can not be terminated despite electrical cardioversion) pulmonary vein isolation combined with linear ablation lesions may be curative.

Patients in Whom Ablation is Appropriate:

Patients with symptomatic paroxysmal AF (episodes that convert spontaneously)
Patients with symptomatic persistent AF (episodes require electrical cardioversion)
Patients with permanent AF (AF can not be terminated despite electrical cardioversion) may soon be candidates for catheter based Maze procedure.
Asymptomatic patients probably should not be considered for pulmonary vein isolation.

Surgical treatment of AF: AF can be cured with an open heart surgical procedure in which a series of lines of electrical conduction block are created to divide the atria into areas of electrically active tissue too small to allow fibrillation. This procedure referred to as the “Maze” procedure can be very effective but requires thorocotomy and cardiopulmonary bypass. Accordingly, the Maze procedure is most commonly reserved for patients who already require open heart surgery for other indications.

What is the best treatment for AF? The various treatment options have not been randomly compared in a scientific study. Antiarrhythmic medication and rate control were compared in an older population with a high percentage of associated heart disease. In this group there was no mortality benefit from rhythm control. This data cannot be extended to guide treatment for younger patients with healthier hearts, nor does it address catheter ablation or surgery. We recommend the following:

Symptomatic patients with paroxysmal or persistent AF consider pulmonary vein isolation or antiarrhythmic therapy for maintenance of normal sinus rhythm.
Asymptomatic patients are treated with rate control and appropriate anticoagulation.

Patients with permanent AF who are undergoing open-heart surgery for treatment unrelated to AF consider a concurrent surgical Maze procedure.