AATAC on AF and HF
Ablation vs amiodarone for a dual epidemic
ACCEL | Heart failure and AF are on the rise and often coexist. The prevalence of AF increases with HF severity, ranging from 5% in NYHA functional class I patients to approximately 50% in class IV patients. Overall, the prevalence of HF in patients with AF has been estimated at 42% with the combination of HF and AF leading to deleterious hemodynamic and symptomatic consequences.
Not surprisingly, evidence suggests that AF may adversely affect mortality, mainly in mild-to-moderate HF, but not in very advanced HF where survival is already limited. Interestingly, new-onset AF appears to portend a particularly dismal prognosis compared with no AF or chronic AF in HF patients.1
The significance of AF in patients with HF with preserved ejection fraction (HFpEF) has been understudied. However, results from the Candesartan in Heart failure-Assessment of Reduction in Mortality and morbidity (CHARM) trial suggest that the attributable risk of AF may be even higher in HFpEF patients.2
What is the optimal approach to managing patients with both HF and AF? Pharmacologic rhythm control has not been shown to improve outcomes compared with pharmacologic rate control, but it is possible that the benefits of maintaining sinus rhythm (SR) are offset by the adverse effects of AADs. Catheter ablation of AF would seem to offer an opportunity to achieve SR without the downside of AADs.
Several studies have shown that AF ablation improves prognostic markers, including ventricular function, exercise tolerance, and perceived quality of life in HF patients. Studies addressing the impact of this treatment strategy on CV outcomes and cost effectiveness are ongoing.
Recently, Luigi Di Biase, MD, PhD, FACC, and colleagues reported the results of the AATAC (Ablation vs. Amiodarone for Treatment of Persistent Atrial Fibrillation in Patients with Congestive Heart Failure and an Implanted Device) trial. The study included 203 patients treated in eight European and U.S. hospitals. All patients had HF with reduced ejection fraction, AF, and either an implantable cardioverter-defibrillator (ICD) or cardiac resynchronization therapy with defibrillator capabilities (CRT-D).
Patients were randomly assigned to catheter ablation or to receive amiodarone and the two groups were well-matched at baseline. Recurrence of AF was the primary endpoint, with all-cause mortality and hospitalization the secondary endpoints. In AATAC, 71% of patients treated with catheter ablation were free of atrial fibrillation, the study’s primary endpoint, after 2 years of follow-up, with only 34% patients who took the AAD free of symptoms at that point (Table).
According to Di Biase, a cardiologist and electrophysiologist at St. David’s Medical Center and the Albert Einstein College of Medicine at Montefiore Hospital, New York, NY, “Even when it is effective, amiodarone often needs to be discontinued after a while due to serious long-term side effects.” For example, in AATAC, amiodarone discontinuation occurred in seven patients due to adverse side effects: four had thyroid toxicity, two pulmonary toxicity, and one patient developed liver dysfunction.
Across the 2-year follow-up, the hospitalization rate was substantially lower in the ablation group (31% vs. 57% in the amiodarone group) and there was a difference in all-cause mortality (TABLE).
Di Biase, the study’s lead author, said, the type and extent of the ablation procedure had a marked impact on the procedure’s success rate. “If the ablation is limited to the pulmonary vein alone, the success rate goes down—almost to the level of the amiodarone treatment,” he said. “The highest success rates were for procedures in which other areas (in addition to the pulmonary vein) were ablated.”
- Aagaard P, Di Biase L, Natale A. Heart Fail Clin. 2015;11:305-17.
- Anter E, Jessup M, Callans DJ. Circulation. 2009;119:2516-25.
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