The 2014 American Heart Association (AHA)/American College of Cardiology (ACC)/Heart Rhythm Society (HRS) guideline for the management of patients with atrial fibrillation provides comprehensive guidance applicable to primary care.1 However, after reviewing it, the Commission on Health of the Public and Science at the American Academy of Family Physicians (AAFP) concluded that the guideline includes recommendations that did not have sufficient supporting evidence. To address this concern, the AAFP updated its guideline on pharmacologic management of newly detected atrial fibrillation,2 which differs in part from the AHA/ACC/HRS guideline. It specifically highlights two questions commonly faced by family physicians, and is based on updated data from the Agency for Healthcare Research and Quality.3,4
Strict vs. Lenient Rate Control
Both guidelines agree that rate control is preferred to rhythm control in most patients with atrial fibrillation. The AHA/ACC/HRS guideline recommends controlling ventricular rate using a beta blocker or nondihydropyridine calcium channel blocker in patients with paroxysmal, persistent, or permanent atrial fibrillation. It also advises that a strict rate control strategy (resting heart rate less than 80 beats per minute) is reasonable for management of atrial fibrillation.1
Many family physicians struggle with a recommendation for such strict control, especially in asymptomatic patients, and are concerned about the potential need for higher doses of medication and the increased risk of medication-related adverse effects. No study definitively shows that strict control improves morbidity or mortality compared with more lenient control. There is some evidence that stroke may be reduced with lenient vs. strict control.5
Although both guidelines agree that data support preferentially using calcium channel blockers and beta blockers over digoxin, there is insufficient evidence to support the superiority of one calcium channel blocker or beta blocker over another.3 The updated AAFP guideline recommends lenient rate control (resting heart rate less than 110 beats per minute) over strict rate control, but it does not recommend specific drug therapies.
Usefulness of Stroke Risk Scores
Using a screening tool to determine a patient's risk of stroke and to inform the shared decision-making process about starting anticoagulation continues to be recommended as good clinical practice. In the AHA/ACC/HRS guideline, the CHA2DS2-VASc score is the recommended screening tool.1 Another screeing tool, the CHADS2 score, uses fewer risk factors; therefore, this AHA/ACC/HRS recommendation for use of the CHA2DS2-VASc score implies that including additional risk factors makes it more likely to identify a patient at risk of stroke. In reality, although the CHA2DS2-VASc score increases the number of patients eligible for anticoagulation, both it and the CHADS2 score are similar in assisting clinicians and patients in determining the risk of stroke.4 In the AAFP guideline, there is no preference for the CHA2DS2-VASc score over the CHADS2 score. The focus is on ensuring that persons with a high risk of stroke are identified, bleeding risk is evaluated, and the overall risks, benefits, and values are openly discussed to reach an optimal patient-centered decision.
Limited but Beneficial Advice
The updated AAFP guideline is limited in scope and does not address all patients with atrial fibrillation; atrial fibrillation due to a reversible cause (e.g., postoperative, post-myocardial infarction, hyperthyroidism) or valvular disease is excluded. The recommendations on rate control and stroke risk assessment are sound, and the guideline is transparent about the strength of the evidence used to reach those conclusions.
editor's note: Dr. Savoy is a member of the AAFP Commission on Health of the Public and Science, which reviewed and approved the AAFP guideline on pharmacologic management of newly detected atrial fibrillation, although she was not an author of the guideline.