Risk factors for stroke should be used to determine whether anti-clotting therapy is given to people with atrial fibrillation, according to revised Guidelines for the Management of Patients with Atrial Fibrillation released today by the American College of Cardiology ( ACC ), American Heart Association ( AHA ) and the European Society of Cardiology ( ESC ).
Atrial fibrillation is the most common heart rhythm disturbance and it increases the risk for stroke, heart failure and all causes of death, especially in women. Presently atrial fibrillation affects more than 2 million Americans and 4.5 million Europeans. The number of patients with atrial fibrillation is expected to increase even more due to an aging population, a rising number of people with chronic heart disease and improved diagnostic possibilities.
Previous guidelines published in 2001 recommended using several patient characteristics – age, gender, heart disease risk and concurrent conditions – to decide proper anti-clotting therapy for these patients. The new approach recommends that the risk for stroke should be the main factor, said Valentin Fuster, co-chair of the guidelines writing committee, and director of the Mount Sinai Cardiovascular Institute in New York.
" We focused on stroke risk because atrial fibrillation is associated with increased long-term risk for stroke," he said. " About 15 percent to 20 percent of strokes occur in people with atrial fibrillation, and those strokes are especially large and disabling.
" Incorporating existing recommendations on anti-clotting therapy from the stroke primary prevention guidelines will streamline patient care and make recommendations clearer for physicians, " he said.
In the United States and Europe, hospital admissions for atrial fibrillation have increased by 66 percent during the last 20 years.
The revised guidelines also recommend daily Acetylsalycilic acid ( Aspirin ) therapy ( 81–325 mg ) to guard against blood clots in atrial fibrillation patients with no stroke risk factors.
Acetylsalycilic acid or Warfarin ( Coumadin ) is recommended for those with one "moderate" risk factor ( over age 75, high blood pressure, heart failure, impaired left ventricular systolic function or diabetes ). Warfarin is recommended for people with any "high" risk factor ( previous stroke, transient ischemic attack [TIA], systematic embolism or prosthetic heart valve ) or more than one moderate risk factor.
According to co-chair Lars E. Rydén, at Karolinska Institutet in Stockholm, Sweden, the guidelines help physicians prioritize the objectives of patient care according to the following steps: 1) controlling heart rate, 2) preventing clots, and, if possible, 3) correcting the rhythm disturbance. Rate control usually involves achieving a ventricular rate of 60 to 80 beats per minute at rest and between 90 and 115 beats per minute during moderate exercise.
Also new in the guidelines, catheter ablation is considered a reasonable alternative to drug therapy to treat atrial fibrillation in patients with little or no left atrial enlargement, and in whom drug treatments did not stop the rhythm disturbance," Fuster said.
Depending on symptoms, controlling the heart rate may be the reasonable therapy in elderly patients with persistent atrial fibrillation who have hypertension or heart disease.
For people under age 70, especially those with recurrent atrial fibrillation and no evidence of underlying heart disease, rhythm control may be the preferred approach, starting with drugs and by means of catheter ablation if medication fails to stop the attacks.
Both Fuster and Rydén emphasized that " Regardless of the approach, the need for anti-clotting therapy should still be based on stroke risk and not on whether proper heart rhythm is maintained."
Source: European Society of Cardiology, 2006
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