Management of Atrial Fibrillation: Guidelines From the American College of Cardiology and American Heart Association

Atrial fibrillation (AF) is expected to impact 12 million people by 2030 and increase mortality risk by at least 1.5 times. It is a chaotic, irregular atrial rhythm caused by ectopic sources in the pulmonary veins of the left atrium or in response to reentrant cardiac conduction activity from interstitial fibrosis. The American College of Cardiology and American Heart Association (ACC/AHA) released guidelines for managing patients with AF.

Clinical evaluation of newly diagnosed AF should include transthoracic echocardiography. Testing for cardiac ischemia and pulmonary embolism is recommended only if suggested by clinical presentation.

Lifestyle Changes

Obesity and physical inactivity are risk factors for AF, but exercise can reduce this risk. Although high-volume exercise of 3 or more hours per day may increase risk, 3.5 hours of moderate to vigorous physical activity weekly is recommended to reduce the incidence of AF and its burden.

Smoking and alcohol consumption increase risk, and quitting reduces risk. In patients with AF, alcohol abstinence and reduction reduce symptoms. Caffeine abstinence does not help reduce AF episodes.

Risk Factor Control

Hypertension is the most important risk factor for AF, and intensive blood pressure control (systolic blood pressure less than 140 mm Hg) reduces risk and recurrence.

Sleep-disordered breathing is another risk factor for AF. Although observational studies suggest treatment decreases the occurrence of AF, small trials show no benefit.

Cryptogenic Stroke

At least 25% of strokes remain cryptogenic after evaluation, and most are presumed to be related to occult AF. Implantable loop recorders detect AF in 30% of patients with cryptogenic stroke or transient ischemic attack over 6 months, compared with 3% with follow-up electrocardiography.

Pharmacologic Stroke Prevention

In AF, anticoagulation therapy is recommended at a CHA₂DS₂-VASc risk (congestive heart failure, hypertension, age ≥ 75 [doubled], diabetes, stroke [doubled], vascular disease, age 65 to 74, sex [female]) score of 2 or greater for men and 3 or greater for women, although treating at a lower score is reasonable. Although the risk of bleeding should be considered, bleeding risk scores are not beneficial.

For patients with moderate to severe mitral stenosis, a mechanical heart valve, or who are receiving P-glycoprotein-inducing agents, warfarin is recommended as the preferred therapeutic agent.

Direct-acting oral anticoagulants (DOACs) are recommended for patients without moderate to severe mitral stenosis or mechanical heart valves because they are equivalent or superior to warfarin for lower bleeding risk. Reduced DOAC doses should be avoided because of increased stroke risk without reduced bleeding risk. Warfarin is an alternative to high-cost DOACs, but it requires more than 70% of time in the therapeutic range for benefit. Aspirin should not be used for stroke prevention, either alone or in combination with clopidogrel.