The quivering and ineffective pumping of the heart during atrial fibrillation (AF) is associated with twice the mortality of persons with normal sinus rhythm. This statistic is one reason revised guidelines on how to treat the condition were recently released by the American College of Cardiology (ACC), the American Heart Association (AHA), and the European Society of Cardiology (ESC). "Guidelines for the Management of Patients with Atrial Fibrillation" was published in the Aug. 15 issue of Circulation. While the 2001 guide placed greater emphasis on using patient characteristics such as age, gender, and heart disease risk, the new guidelines highlight stroke risk as the primary means to determine the need for anticoagulants.
"We focused on stroke risk because AF is associated with increased long-term risk for stroke," said Valentin Fuster, M.D., Ph.D., co-chair of the guidelines-writing committee. In fact, according to the new guidelines, the rate of ischemic stroke in patients with nonvalvular AF is two to seven times that of people without AF, and the risk increases dramatically as patients age. Also, strokes associated with AF are especially severe and disabling, said Fuster.
The new guidelines recommend daily aspirin (81 to 325 mg) to guard against blood clots in AF patients with no stroke risk factors. For patients with one moderate risk factor, such as age over 75 years, hypertension, heart failure, diabetes, or impaired left ventricular systolic function, either aspirin or warfarin is the drug of choice. Patients with any high-level risk factor (previous stroke, transient ischemic attack, prosthetic heart valve, or systemic embolism) or more than one moderate risk factor should receive warfarin (see table).