Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.
Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.
The choice of medication depends on the type of atrial fibrillation diagnosed, the underlying cause, other medical conditions that contribute to the patient's overall health, and other medications. Ironically, many antiarrhythmia medications may induce abnormal heart rhythms.
Antiarrhythmia medications include:
Miscellaneous antiarrhythmia medications: These drugs control the heart rhythm rather than the rate. They reduce the frequency and duration of atrial fibrillation episodes. They are often given to prevent the return of atrial fibrillation after cardioversion. The most commonly used drugs are amiodarone (Cordarone, Pacerone), sotalol (Betapace), propafenone (Rythmol), and flecainide (Tambocor). Overall, these drugs are 50%-70% effective.
Beta-blockers: These drugs slow the heart rate by decreasing the rate of the SA node and by slowing conduction through the AV node. Therefore, the heart's demand for oxygen is decreased, and the blood pressure is stabilized. Examples include esmolol (Brevibloc), atenolol (Tenormin), propranolol (Inderal), or metoprolol (Lopressor, Toprol XL).
Calcium channel blockers: These drugs also slow heart rate by mechanisms similar to those of beta-blockers. Verapamil (Calan, Isoptin) and diltiazem (Cardizem) are examples of calcium channel blockers.
Digoxin (Lanoxin): This drug decreases the conductivity of electrical impulses through the AV node, but onset of action is slower than beta-blockers and calcium blockers. Digoxin is currently used primarily in patients with associated heart disease, such as a poorly functioning left ventricle.
Dofetilide (Tikosyn): This is an oral antiarrhythmic drug that must be initiated in the hospital over a three-day period. Hospitalization is needed to closely monitor the heart rhythm during the initial dosing period. If the atrial fibrillation responds favorably during the initial dosing, a maintenance dose is established to be continued at home.
Other medications: There are many other drugs in use and they are prescribed to individualize the treatment of A fib. Other drugs can include Ibutilide (Corvert), Dronedarone (Multaq), and Quinidine (Cardioquin, Quinalan, Quinidex, Quinaglute); others may be used rarely.
Herbs: Some herbal companies claim cures of atrial fibrillation with their product, but the data to support these claims is questionable and not acceptable to most researchers.
Other drugs are used to help patients avoid blood clot formation that may lead to strokes or additional health problems. The decision to utilize other drugs can be augmented by the CHADS2 score that assigns points to various conditions (congestive heart failure, hypertension, age, diabetes, and previous stroke) in an A fib patient. The higher the points, the more likely the patient is to develop a stroke; some clinicians use this score to help determine what other drugs may help their patients with A fib avoid a stroke.
Warfarin (Coumadin): This drug is an anticoagulant (blood thinner). It reduces the ability of the blood to clot. It lowers the risk of an unwanted blood clot forming in the heart or in a blood vessel. Atrial fibrillation increases the risk of forming such blood clots. It is extremely important to follow the exact dosing prescribed and to have regular blood tests (International Normalized Ratio [INR]) when recommended by the doctor. Patients are urged to keep these important appointments to reduce their risk of blood clot formation or the risk of having an excessive tendency to bleed.
Eliquis: This new drug, reported to be better than warfarin for A fib treatment, has been delayed in its FDA approval.
Aspirin and clopidogrel (Plavix): These are two commonly prescribed drugs used to reduce the chance of clot development in A fib patients, especially if patients cannot tolerate Coumadin; they also have been used in short-term treatments while a patient is undergoing evaluation for clot formation.
Heparin and enoxaparin (Lovenox): These similar drugs have been used in short-term treatment of A fib patients; occasionally, Lovenox has been used by some physicians for longer term treatment.
Dabigatran (Pradaxa): This thrombin inhibitor is approved for
prevention of strokes and thrombus in nonvalvular A fib. There is some
controversy about this new drug causing increased heart problems.
Rivaroxaban (Xarelto): This factor Xa inhibitor is approved for
the prevention of strokes and embolisms associated with nonvalvular A fib;
dosing is related to creatinine clearance (CrCl) levels (kidney function).