AF Ablation in Patients with Persistant AF and CHF
What percentage of atrial fibrillation (AF) patients with an ICD and congestive heart failure can be considered for catheter ablation?
AF Symposium News spoke with Andrea Natale, MD (Texas Cardiac Arrhythmia Institute at St. David’s Medical Center, Austin, Texas) in a live interview on site at the meeting. “It really depends on the center. In our center, it’s probably 2-3%. Although it’s not a huge number, if you look at the progression wit heart failure, AF is a big problem in the subset of patients. Not only is it an issue in terms of quality of life, but AF is always a predictor of mortality, so it’s actually a very important issue in the heart failure group.”
Studying ablation in this particular patient population is particularly important. “ The combination of AF and heart failure makes management of these patients more difficult, because everything deteriorates with AF,” said Dr. Natale. With some of the data that we have seen in this randomized study, there might be a different impetus to consider ablation, because it potentially could have an impact of mortality.”
Long-term result of the multicenter Ablation vs Amiodarone for Treatment of Atrial Fibrillation in Patients with Congestive Heart Failure and an Implanted ICD/CRT-D (AATAC-AF) study, presented during the American College of Cardiology’s 64th Annual Scientific Sessions in March 2015 by Dr. Luigi Di Biase (Albert Einstein/Montefiore Hospital, New York) and colleagues, demonstrated that catheter ablation of persistent AF was superior to amiodarone in achieving freedom from AF at long-term follow-up as well as reducing hospitalization and mortality in patients with heart failure (HF). Unlike with many previous catheter ablation trials that enroll patients with preserved left ventricular (LV) systolic dysfunction. AF and HF frequently coexist and are often associated with several common predisposing risk factors. The prevalence of AF increases with HF severity (e.g., from 5% in functional class I patients to approximately 50% in class IV patients), and the prevalence of HF and AF can lead to deleterious hemodynamic and symptomatic consequences.
In the randomized AATAC-AF study, 203 patients were enrolled and randomly assigned (1:1 ratio) to undergo catheter ablation (group 1, n=102) or receive amiodarone (group 2, n=101). Patients ≥18 years of age with persistent AF and a dual-chamber ICD or CRT-D, NYHA II-III, and LVEF ≤40% within the last six months were included in this trial. Results showed that 71 patients in group 1 vs 34 patients in group 2 were AF recurrence-free post treatment. Furthermore, of the 102 patients who underwent catheter ablation, a higher success rate was shown in the patients undergoing PVI plus (78.8%) compared to PVI alone (36.4%). At the end of follow-up, recurrence-free patients (n=105) also experienced significantly better improvement in all parameters compared to those who experienced recurrence (n=98). Over the 2-year follow-up, the hospitalization rate (31% vs 57%) and all-cause mortality (8% vs 18%) were lower in group 1.
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Dr. Natale explained: “The study we did included patients with persistent AF, and we realized that in this subgroup, there was no consensus on treatment. So we planned to look at the different outcomes based on strategy. WE found that pulmonary vein isolation alone was not better than amiodarone. The outcome really depended on what was done during the procedure, and clearly this was a group where pulmonary vein isolation alone, the success rate was about 35%. Center that used an additional strategy achieved a better success rate, about 60-70% in a single procedure.”
These findings demonstrate that ablation is a viable option for AF patients with congestive heart failure. Are the trial’s findings also generalizable to heart-failure patients without an implanted device? “The study evaluated a group of patients with an implantable device and systolic dysfunction. There is more data on diastolic dysfunction, which clinically can manifest as heart failure, but they do not have a deterioration or left ventricular function. In that group there is data that ablation is effective, but again, there is a higher recurrence rate long term. So heart failure patients, regardless whether with low EF or normal EF, are clearly a group where we need to look beyond the pulmonary vein.”
Dr. Natale discussed how these finding could impact current clinical practice. “I think these findings can change how aggressive people manage AF in this group. In the past, I think most people tried to increase the dose of antiarrhythmic drugs, primarily amiodarone, which we know has a toxic effect over time. This new information will encourage people to consider ablation sooner.”
He continued: “In patients with HF, atrial fibrillation is considered a nuisance, and many clinicians believe patients can live with it. However, this study shows the benefit of catheter ablation in these patients,” said Dr. Natale, principal investigator. “I believe that ablation should not be considered as a ‘salvation’ for these patients, but as a feasible and effective treatment when compared to the most efficacious drug that is amiodarone.”
Further investigation into the potential socioeconomic repercussion of these results is needed. In 2016, Natale added, “We will be doing a broader study looking at what is considered standard of care. We will focus on determining the best strategy beyond the pulmonary vein. That is where the field needs to move. In paroxysmal patients, I think we can agree that the pulmonary vein is an important target. In nonparoxysmal patients, we need to figure out a strategy that everyone can use with similar results, although we have yet to determine what that strategy is.”