The treatment of AF is multi-faceted and involves 1) reversing the factors that cause AF, 2) slowing the heart rate with medications, 3) preventing strokes, 4) converting AF to a normal heart rhythm with medications or electrical shock, 5) preventing the recurrence of AF with medications, and 6) using procedures (e.g., pacemakers, defibrillators, surgery) to prevent episodes of AF.
Reversing the risk factors that cause atrial fibrillation An important first step in the treatment of atrial fibrillation is to uncover and correct conditions (such as hyperthyroidism or use of stimulant drugs) that can cause atrial fibrillation. These steps include:
Stopping the use of stimulant drugs and excessive alcohol intake
Controlling high blood pressure
Correcting hyperthyroidism (too much thyroid hormone) and low blood oxygen levels
Controlling heart failure and treating the diseases of the heart and the lungs that can cause AF
Slowing the heart rate with medications Having excluded or corrected the factors that cause AF, the next step when the ventricles are beating too rapidly usually is to slow the rate at which the ventricles beat.
Available medications. Patients with AF and healthy AV nodes usually have ventricles that beat rapidly. Medications are necessary to slow down the rapid heart rate. Medications to slow the heart rate in AF include:
Beta blockers such as propranol (Inderal), atenolol (Tenormin), metoprolol (Lopressor), esmolol (Brevibloc)
Calcium channel blockers such as verapamil (Calan), diltiazem (Cardizem)
These medications slow the heart rate by retarding conduction of the electrical discharges through the AV node. These medications, however, do not usually convert AF back into a normal rhythm. Other drugs or treatments are necessary to achieve a normal heart rhythm.
Benefits of controlling the rate. In patients with rapid ventricle contractions as a result of AF, slowing the rate of ventricular contractions improves the heart's efficiency in delivering blood (by allowing more time between contractions for the ventricles to fill with blood) and relieves the symptoms of inadequate flow of blood - dizziness, weakness, and shortness of breath.
With chronic, sustained AF, doctors may decide to leave some patients in AF provided that their heart rates are under control, the output of blood from the ventricles is adequate, and their blood is adequately thinned to prevent strokes. This form of treatment is called rate control therapy (see below).
Limitations of medications for controlling the heart rate. In patients with diseased AV nodes, ventricular contractions may be slower than patients who have normal AV nodes. Moreover, some elderly patients with AF are extremely sensitive to medications that slow the rate of ventricular contractions, usually because of a diseased AV node. In these patients, the heart rate can become dangerously slow with small doses of medications to slow the heart. This condition is referred to as tachycardia-bradycardia syndrome, or "sick sinus syndrome." Patients with tachycardia-bradycardia syndrome need medications to control the fast heart rate and a pacemaker to provide a minimum safe heart rate.
Medications used in slowing AF generally cannot convert AF to a normal rhythm. Therefore these patients are at risk for the formation of blood clots in the heart and strokes and will need prolonged blood thinning with anticoagulants like warfarin (Coumadil).