The Interruption of Anticoagulation section of our article on Treatment of Atrial Fibrillation cited the recommendations of the American College of Chest Physicians on perioperative management of antithrombotic therapy (JD Douketis et al. Chest 2022; 162:e207). A reader suggested that our general statement on when to discontinue an oral anticoagulant would have benefited from inclusion of the recommendations of the American College of Cardiology/American Heart Association (JA Joglar et al. Circulation 2024; 149:e1). Recommendations for periprocedural management of oral anticoagulant therapy vary with the anticoagulant, the bleeding risk of the patient and the procedure, the patient’s thromboembolic risk (CHA₂DS₂-VASc score), the presence of a mechanical valve, and for some anticoagulants, the patient’s renal function. These recommendations are provided in detail in both of the above-cited guidelines.

Atrial fibrillation (AF) is the most common arrhythmia in the world. Risk factor modification, anticoagulation, rhythm control, and rate control are the four pillars of its management. American College of Cardiology/American Heart Association (ACC/AHA) guidelines on management of AF were updated recently.

The centuries-old anti-inflammatory drug colchicine (Colcrys, and others) is FDA-approved for prophylaxis and treatment of gout flares and for treatment of familial Mediterranean fever. It is also used off-label to treat pericarditis, and in recent years has been investigated for reduction of cardiovascular risk in patients with coronary artery disease (CAD).

Treatment of atrial fibrillation includes anticoagulation, rate control, and rhythm control. US guidelines were recently updated.

With the widespread adoption of the CHA₂DS₂-VASc scoring system, oral anticoagulation therapy is now recommended for all patients ≥75 years old with nonvalvular atrial fibrillation. Atrial fibrillation has, however, been associated with an increased risk of falls, and older patients starting warfarin for atrial fibrillation have a high rate of hospitalization for intracranial bleeding. Many practitioners are reluctant, therefore, to prescribe an oral anticoagulant for elderly patients who are at high risk for falls.

Direct-to-consumer advertisements continue to urge patients who take warfarin (Coumadin, and others) for atrial fibrillation to ask their doctors about the benefits of one or another of the newer oral anticoagulants.

The FDA has approved edoxaban (Savaysa – Daiichi Sankyo), a once-daily, oral, direct factor Xa inhibitor, for treatment of venous thromoboembolism (VTE) and for prevention of stroke and systemic embolism in patients with nonvalvular atrial fibrillation. It is the fourth new oral anticoagulant to be approved for VTE and nonvalvular atrial fibrillation.

The treatment of atrial fibrillation includes anticoagulation, rate control, and rhythm control. New US guidelines for the management of atrial fibrillation have recently been published.

Full-page newspaper advertisements and a series of television commercials have urged patients with atrial fibrillation to "rethink warfarin" in favor of Eliquis (apixaban – Bristol-Myers Squibb). Apixaban is the latest of 3 new oral anticoagulants now competing with warfarin (Coumadin, and others) for the oral anticoagulant market.

The FDA has approved apixaban (Eliquis – Bristol-Myers Squibb/Pfizer), an oral direct factor Xa inhibitor, for prevention of stroke and systemic embolism in patients with nonvalvular atrial fibrillation. It is the third new oral anticoagulant to be approved for this indication as an alternative to warfarin.

Atrial fibrillation increases the risk of thromboembolic stroke. Anticoagulant therapy can reduce this risk and is recommended for patients with atrial fibrillation and one or more of the following: congestive heart failure, hypertension, age ≥75 years, diabetes, or prior stroke or transient ischemic attack (CHADS₂ score ≥1).

The labeling of dabigatran etexilate (Pradaxa – Boehringer Ingelheim), an oral direct thrombin inhibitor, has recently been updated to include new dosing and monitoring recommendations and a warning on the risk of bleeding. Dabigatran etexilate was approved in the US in 2010 for the prevention of thromboembolic stroke in patients with non-valvular atrial fibrillation. It has been shown to be more effective than warfarin (Coumadin, and others) for this indication.

Dronedarone (Multaq – Sanofi), an analog of amiodarone, was approved by the FDA in 2009 for oral treatment of paroxysmal or persistent (non-permanent) atrial fibrillation or atrial flutter. Amiodarone (Cordarone, and others) is more effective for this indication, but its use is often limited by its adverse effects, including thyroid and pulmonary toxicity.

Arterial thrombi are composed mainly of platelet aggregates held together by small amounts of fibrin. Antiplatelet drugs are the drugs of choice for prevention and treatment of arterial thrombosis, but anticoagulants are also effective, and their effects can add to those of antiplatelet drugs. Venous thrombi are composed mainly of fibrin and trapped red blood cells, with relatively few platelets. Anticoagulants are the agents of choice for prevention and treatment of venous thromboembolism and for prevention of cardioembolic events in patients with atrial fibrillation.

The FDA has approved rivaroxaban (Xarelto – Janssen), an oral direct factor Xa inhibitor, for prevention of deep vein thrombosis (DVT) in patients undergoing knee or hip replacement surgery.

The FDA and the manufacturer (Sanofi-Aventis) have warned healthcare professionals that use of dronedarone (Multaq), an analog of amiodarone (Cordarone, and others) approved in 2009 for treatment of atrial fibrillation,1,2 has been associated with "several" cases of severe liver injury and hepatic failure, including two that required liver transplants. Both transplants were in women about 70 years old; one had taken the drug for 4.5 months and the other for 6 months. According to the FDA, 147,000 patients have taken dronedarone.3 A new warning in the package insert recommends monitoring hepatic enzymes, especially during the first 6 months of treatment.

1. Dronedarone (Multaq) for atrial fibrillation. Med Lett Drugs Ther 2009; 51:78.

2. Treatment of atrial fibrillation. Treat Guidel Med Lett 2010; 8:65.

3. FDA drug safety podcast for healthcare professionals: severe liver injury associated with the use of dronedarone (marketed as Multaq). Available at www.fda.gov. Accessed February 24, 2011.

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The FDA has approved the oral direct thrombin inhibitor dabigatran (da big’ a tran) etexilate (Pradaxa – Boehringer Ingelheim) for prevention of thromboembolic stroke in patients with non-valvular atrial fibrillation. It has been available in Canada (Pradax) since 2008 for prevention of thromboembolism in patients undergoing knee or hip replacement surgery and was recently approved there for use in atrial fibrillation.

The treatment of atrial fibrillation includes ventricular rate control, anticoagulation, conversion to normal sinus rhythm and maintenance of sinus rhythm. The choice of therapies that can achieve these goals is discussed in the text that follows. Some drugs are recommended here for indications that have not been approved by the FDA.

Dronedarone (Multaq - Sanofi-Aventis) has been approved by the FDA for oral treatment of atrial fibrillation and flutter. Amiodarone (Cordarone, and others) is the most effective drug for this indication, but has considerable toxicity.

Atrial fibrillation increases the risk of stroke by a factor of 5. A randomized controlled trial (ACTIVE W) in 6706 patients with atrial fibrillation and one or more additional risk factors (≥75 years old; hypertension; previous stroke, transient ischemic attack or non- CNS embolus; left ventricular ejection fraction <45%; peripheral vascular disease; or 55-74 years old plus diabetes or coronary artery disease) found that a vitamin K antagonist such as warfarin (Coumadin, and others) was superior to clopidogrel (Plavix) plus aspirin in preventing vascular events, especially ischemic stroke.1

Now another study (ACTIVE A) from the same group of investigators has compared addition of clopidogrel to aspirin with aspirin alone in 7554 patients with atrial fibrillation and one or more additional risk factors for stroke. All of these patients were considered “unsuitable” for treatment with a vitamin K antagonist. Vascular events, primarily stroke, occurred significantly more often with aspirin alone. Major bleeding occurred significantly more often with aspirin plus clopidogrel.2

Oral anticoagulation with a vitamin K antagonist such as warfarin continues to be the treatment of choice for patients with atrial fibrillation and one or more additional risk factors for stroke.3-5 In patients who cannot or will not take a vitamin K antagonist, clopidogrel plus aspirin appears to be more effective in preventing stroke than aspirin alone.

1. ACTIVE Writing Group of the ACTIVE Investigators. Clopidogrel plus aspirin versus oral anticoagulation for atrial fibrillation in the Atrial fibrillation Clopidogrel Trial with Irbesartan for prevention of Vascular Events (ACTIVE W): a randomised controlled trial. Lancet 2006; 367:1903.

2. ACTIVE Investigators. Effect of clopidogrel added to aspirin in patients with atrial fibrillation. N Engl J Med 2009; 360:2066.

3. Antiplatelet and anticoagulant drugs. Treat Guidel Med Lett 2008; 6:29.

4. DE Singer et al. Antithrombotic therapy in atrial fibrillation: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition). Chest 2008; 133 (6 suppl): 546S.

5. AS Go. The ACTIVE pursuit of stroke prevention in patients with atrial fibrillation. N Engl J Med 2009; 360:2127.

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Arterial and venous thrombosis are major causes of morbidity and mortality. Arterial thrombi consist of platelet aggregates held together by small amounts of fibrin. Antiplatelet drugs are the drugs of choice for prevention and treatment of arterial thrombosis, but anticoagulants are also effective, and their effects can add to those of antiplatelet drugs. Venous thrombi are composed mainly of fibrin and trapped red blood cells, with relatively few platelets. Anticoagulants are the agents of choice for prevention and treatment of venous thromboembolism and for prevention of cardioembolic events in patients with atrial fibrillation.

The drugs of choice for treatment of common cardiac arrhythmias are listed in Tables 1 and 2. Some drugs are recommended for indications that have not been approved by the FDA.

The drugs of choice for treatment of common cardiac arrhythmias are listed in the table that begins on the next page; some drugs are recommended for indications for which they have not been approved by the US FDA. The dosages and adverse effects of each drug are listed in the table that begins on page 80. Antiarrhythmic drugs may themselves cause arrhythmias, which can be fatal. Some of these drugs may increase rather than decrease mortality, especially in patients with structural heart disease.

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