Application of the findings from the AATAC randomized clinical trial may potentially lead to an increased use of catheter ablation in patients with atrial fibrillation (AFib) and heart failure with reduced ejection fraction (HFrEF), suggests Jehu S. Mathew, MD, et al., in an analysis using NCDR data published August 11 in the Journal of the American Heart Association.

Their study is part of ACC's Research to Practice (R2P) initiative, which identifies impactful cardiovascular research and analyzes its implications for contemporary clinical practice by facilitating rapid analysis of NCDR registry data. In this case, researchers used ACC's PINNACLE Registry to understand the impact of the AATAC trial, which showed catheter ablation to be beneficial in appropriately selected HFrEF patients. Study authors identified 8,483 patients between 2013 and 2014 who met AATAC enrollment criteria and compared their patterns of antiarrhythmic drugs (AADs) and procedural use with the AATAC trial population.

Compared with the AATAC trial population, PINNACLE Registry patients eligible for AATAC were older (mean age, 71.2 ± 11.2 years vs. 61 ± 11 years), had greater comorbidity (hypertension 82.4 percent, coronary artery disease 79.2 percent and diabetes 31.8 percent) and were on more medical therapy (all patients were taking an angiotensin-converting enzyme inhibitor and beta-blocker).

While all patients in the AATAC trial had persistent AFib, within this PINNACLE Registry analysis only 16.7 percent of patients had persistent or permanent AFib. Most (65.5 percent) had paroxysmal AFib and 17.8 percent had new-onset AFib. Regarding atrioventricular-nodal blocking agents, most used carvedilol (71.2 percent), followed by digoxin (31.9 percent) and metoprolol (27.1 percent). Researchers also found that rate control was used as the predominant strategy and beta-blockers were the preferred medication in the studied population.

Nearly a third of patients used AADs, most commonly amiodarone, for rhythm control. Only 9.3 percent underwent catheter ablation and those who did were typically younger with fewer comorbidities. Researchers found variation in ablation volume by sites (median rate 0.1 ablations/year). Nearly half of participating sites did not perform AFib ablation in this population; however, three sites had rates exceeding 25 percent. "As a result, referral for AF[ib] ablation may also reflect not only patient specific differences, but also regional and system-wide differences that may favor rate control over rhythm control," note the study authors.

They note that while these R2P study results "reflect[s] recent practice, the AATAC findings became available after these data were collected." To improve the understanding of catheter ablation in this population, the authors suggest focusing on "patient symptoms, quality of life, and real-world outcomes" in future studies, recognizing "major limitations imposed by treatment selection in observational data."

Keywords: Anti-Arrhythmia Agents, Amiodarone, Atrial Fibrillation, Metoprolol, Angiotensin-Converting Enzyme Inhibitors, Catheter Ablation, Digoxin, Comorbidity, Coronary Artery Disease, American Heart Association, Research Personnel, Stroke Volume, Quality of Life, Propanolamines, Carbazoles, Adrenergic beta-Antagonists, Heart Failure, Hypertension, Diabetes Mellitus, Registries, Referral and Consultation

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