By Joshua Moss, MD

Associate Professor of Clinical Medicine, Cardiac Electrophysiology, Division of Cardiology, University of California, San Francisco

Dr. Moss reports he is a consultant for Abbott, Boston Scientific, and Medtronic.

SYNOPSIS: This focused update to the 2014 guidelines for the management of atrial fibrillation (AF) includes revisions to anticoagulation recommendations and the role of catheter ablation of AF in patients with heart failure.

SOURCE: January CT, et al. 2019 AHA/ACC/HRS focused update of the 2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation: A report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. J Am Coll Cardiol 2019; Jan 21. pii: S0735-1097(19)30209-8. doi: 10.1016/j.jacc.2019.01.011. [Epub ahead of print].

Numerous landmark studies relevant to atrial fibrillation (AF) management have been published since the comprehensive 2014 American Heart Association/American College of Cardiology/Heart Rhythm Society guidelines were released. The 2019 focused update reflects new data regarding oral anticoagulant choices, AF in patients with acute coronary syndrome and heart failure, ambulatory device detection of AF, and weight loss.

For the prevention of AF-related stroke, edoxaban is now included in the recommended list of non-vitamin K oral anticoagulants (NOACs). All NOACs (dabigatran, rivaroxaban, apixaban, and edoxaban) are preferred to warfarin unless there is moderate-to-severe mitral stenosis or a mechanical heart valve (Class I, Level A). Also, apixaban is the recommended alternative to coumadin for those with chronic kidney disease (CrCl < 15mL/min) or on dialysis (Class IIb, Level B-NR).

The update also provides new guidance on the use of the NOAC reversal agents. If there is a life-threatening bleeding event or an urgent procedure, idarucizumab is recommended for reversal of dabigatran (Class I, Level B-NR) and andexanet alfa for the reversal of rivaroxaban and apixaban (Class IIa, Level B-NR). Finally, in those who are contraindicated to long-term anticoagulation, percutaneous left atrial appendage occlusion may be considered in AF patients with a higher risk of stroke (Class IIb, Level B-NR).

The use of oral anticoagulants for AF in the setting of acute coronary syndrome also has been revised. In those who have undergone percutaneous coronary intervention for ACS, double therapy with clopidogrel and low-dose rivaroxaban (15 mg daily) or dabigatran (150 mg twice daily) is reasonable to reduce the risk of bleeding compared with triple therapy (Class IIa, Level B-R). In patients with heart failure with reduced ejection fraction, catheter ablation of AF is reasonable, as it has been shown to lower the mortality rate and reduce heart failure hospitalizations (Class IIb, Level B-R).

Finally, there are new statements regarding ambulatory device detection of AF and weight loss. A loop recorder is reasonable for silent AF detection in patients with cryptogenic stroke and inconclusive ambulatory monitoring. In overweight and obese patients with AF, weight loss and modification of other key risk factors (including, but not limited to, sleep apnea, hypertension, alcohol, and smoking) are recommended (Class I, Level B-R).

COMMENTARY

These revisions arrive at an important time following numerous practice-changing publications. Obesity is associated with atrial remodeling and increasingly is recognized as both a risk factor for AF and a barrier to maintenance of sinus rhythm. Lifestyle modifications and weight loss, both via bariatric surgery and structured weight management programs, have been shown to reduce AF episodes and severity of AF-related symptoms convincingly.

The use of NOACs as first-line therapy for thromboembolic prophylaxis now carries a Class IA recommendation, although this has been the standard practice for most cardiologists and electrophysiologists for several years. That said, warfarin remains the first-line therapy for patients with moderate-to-severe mitral stenosis or a mechanical heart valve. Optimal therapy for patients with bioprosthetic heart valves is uncertain, although limited data suggest that apixaban and edoxaban are noninferior to warfarin in that population. Additional studies may be needed before routine recommendation of NOACs in the setting of AF and bioprosthetic valves. The recommendation for loop recorder implant for detection of “silent AF” is not surprising, considering both the ease of implant and the growing evidence to suggest sensitivity increases dramatically beyond several weeks of monitoring. However, the potential implications for use of consumer products, such as the Kardia monitor or the Apple Watch, will be interesting to follow. While there is no published consensus, “incidentally” detected AF is likely to be treated no differently by the cardiology community than more “traditionally” diagnosed AF. Thus, clinicians will need to consider and follow anticoagulation guidelines pending risk evaluation while taking care not to overtreat asymptomatic AF in patients without other sequelae such as cardiomyopathy.

The role of catheter ablation for AF continues to evolve rapidly. Multiple randomized trials published since 2014 have been taken into consideration with the new guidelines. In 2016, the results of the AATAC trial demonstrated that AF ablation was superior to amiodarone in maintaining sinus rhythm and reducing heart failure hospitalizations and mortality in patients with cardiomyopathy and heart failure. In 2017, CAMERA-MRI showed superiority of AF ablation over medical rate control in improving left ventricular ejection fraction (LVEF), six-minute walk test performance, and quality of life in patients with cardiomyopathy and persistent AF. In 2018, CASTLE-AF showed that heart failure patients who underwent catheter ablation for AF demonstrated reduced mortality, fewer hospitalizations for worsening heart failure, and better LVEF compared to the medical therapy group. That the focused update only assigns a Class IIb, Level B-R recommendation for catheter ablation in patients with AF and heart failure suggests that the task force believed some or all these studies provided only moderate-quality evidence. Indeed, there were important limitations to each study.

Nevertheless, referral of patients with reduced LVEF, heart failure symptoms, and paroxysmal or persistent AF for catheter ablation should be considered early — certainly prior to committing patients to long-term amiodarone or if a potentially recoverable cardiomyopathy AF is eliminated.