According to the revised Acc Aha Esc Guidelines for the Management of Patients with Atrial Fibrillation released today, Risk factors for Stroke should be used to determine whether anticoagulation therapy is given to people with atrial fibrillation.

Atrial fibrillation (AF) is the most common heart rhythm disturbance and it increases the risk of stroke, heart failure and all-cause death. It 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 diagnosis.

During AF, two upper chambers of the heart (the atria) quiver instead of beating effectively. Blood is not pumped completely out of them, so it may pool and clot. If a piece of a blood clot in the atria leaves the heart and lodges in an artery in the brain, a stroke results. Moreover, when the very rapid electrical signals from the atria reach the lower chambers of the heart (the ventricles) they start to beat quickly and irregularly causing palpitations and decreased blood pumping leading to
tiredness and breathlessness.

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, M.D., Ph.D., co-chair of the guidelines writing committee.

"We focused on stroke risk because AF is associated with increased long-term risk for stroke", he said. "About 15 percent to 20 percent of strokes occur in people with AF, 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 added.

AF is expensive, with total costs approaching €13.5 billion in the European Union alone, according to the statement.

The revised guidelines also recommend daily aspirin therapy (81–325 mg) to guard against blood clots in AF patients with no stroke risk factors. Aspirin or warfarin 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], systemic embolism or prosthetic heart valve) or more than one moderate risk factor.

According to co-chair Lars E. Rydén, 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 (pulse) 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 — a procedure that corrects irregular heartbeat with radiofrequency energy — is considered “a reasonable alternative to drug therapy to treat AF 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 AF who have hypertension or heart disease, according to the joint statement.

For people under age 70, especially those with recurrent AF 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

Full guidelines are available at many websites including ACC page for scientific statements