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Response by Di Biase et al to Letter Regarding Article, “Ablation Versus Amiodarone for Treatment of Persistent Atrial Fibrillation in Patients With Congestive Heart Failure and an Implanted Device: Results From the AATAC Multicenter Randomized Trial”

Originally published 2016;134:e189–e190

    In Response:

    We read with interest the letters by Kosiuk et al, Skolnik, Turco, Liu and Yang, and Willey and Biviano.

    We thank these authors for their interest in our study.

    We agree with Kosiuk et al that the restoration of sinus rhythm in patients with heart failure and persistent atrial fibrillation (AF) is key to improving ejection fraction and 6-minute walk distance, and we agree with the authors’ data showing a reduction of inappropriate shocks attributable to atrial arrhythmias in patients undergoing ablation.1 Unfortunately, in our trial,2 we did not prospectively collect implantable cardioverter defibrillator inappropriate shocks, and we will not be able to provide solid data.

    We respectfully disagree with the idea of Dr Skolnik. As mentioned in the discussion and in the clinical perspective of the article, we are not proposing AF ablation in all patients with heart failure, but we are suggesting that this underused therapeutic approach is considered more and more in patients with heart failure.2 The PABA CHF (Comparison of Pulmonary Vein Isolation Versus AV Nodal Ablation With Biventricular Pacing for Patients With Atrial Fibrillation With Congestive Heart Failure) trial,3 although small, showed little improvement with the atrioventricular node ablation and cardiac resynchronization therapy (CRT) device implantation in comparison with ablation. In addition, because all patients had a device, we would like to highlight that rate control was achieved in the majority of the patients. Amiodarone is per se a rate control medication and >75% of the patients were on optimal β-blocker therapy in both arms as shown in Table 1.2 Therefore, we do think that sinus rhythm restoration should be attempted in these patients if their clinical status allows. We agree with Dr Skolnik that the data of this trial cannot be applied to all patients with heart failure and AF especially when their clinical status is so deteriorated that any invasive intervention is discouraged.

    We agree with the letter by Dr Turco. As previously mentioned, restoration of sinus rhythm in patients with heart failure improves the prognosis. The role of atrioventricular node ablation was not explored in this trial, and, therefore, we cannot comment on this, but, as mentioned above, patients had good rate control. The possible role of CRT defibrillator versus implantable cardioverter defibrillator (also commented on by Liu and Yang) in the outcome was not part of the study design. However, 72% patients of the overall population (74% in catheter ablation group and 71% in the amiodarone group, P=0.72) had an implantable cardioverter defibrillator, and the type of device did not show any association with the primary outcome.

    Although we agree with Dr Turco’s comments on the correlation between left atrial volume, strain rate, and MRI, these were not part of the study design. However, in the patients enrolled in our study, we have very rarely observed the resolution of AF after CRT therapy. Finally, the CRT patients considered for the study had AF despite CRT therapy.

    In regard to the comments of Liu and Yang, we would like to point out that the recurrence-free rate from AF in the AATAC (Ablation vs Amiodarone for Treatment of Atrial Fibrillation in Patients With Congestive Heart Failure and an Implanted ICD/CRTD) trial is higher than in the RAAFT-2 (Radiofrequency Ablation vs Antiarrhythmic Drugs as First-Line Therapy of Atrial Fibrillation 2) trial4 because of a more extensive ablation strategy, the possibility of performing >1 procedure in the blanking period, and the higher level of experience of the operators involved in the study.

    Our study presented robust results to support our primary conclusions. However, when analyses are to be performed based on alternative clinical questions, for which the trial was not designed, the statistical uncertainty of such comparisons involves consideration of the potential bias. Therefore, in the context of the comments from Liu and Yang, if a different success rate between pulmonary vein isolation alone and pulmonary vein isolation plus posterior wall isolation impacted the mortality or hospitalization, we consider that our study did not have sufficient information to draw the inference.

    Similarly, with respect to comparing mortality between pulmonary vein isolation alone and amiodarone, given the small number of events in group 1, we consider that such an effort will suffer from small-sample bias and will lead to unwarranted estimates. Having such a small number of events in the numerator, the estimate will be unable to capture the true underlying rate of the population.

    The Tang et al5 study, which the authors referred to, had a 40-month follow-up duration. This is substantially longer than our 24-month follow-up. That is a major difference and explains, in most part, the lower mortality observed by our study.

    The Cox model in our analysis was fitted with covariates, age, sex, diabetes mellitus, and hypertension, that have shown an established or likely association with ablation outcome. Although anticoagulation strategy, CHA2DS2-VASc scores, and aldosterone antagonist use are important risk factors, expanding the covariate list with the given sample size had the risk of running into model overfitting. Besides, we did not see any significant association of these variables at the univariate label.

    Finally, although the comments by Willey and Biviano are appropriate, no stroke occurred in our series during the procedure and at follow-up. However, all our patients were on oral anticoagulation before and after catheter ablation.

    Luigi Di Biase, MD, PhDPrasant Mohanty, MBBS, MPHSanghamitra Mohanty, MDPasquale Santangeli, MDChintan Trivedi, MD, MPHDhanunjaya Lakkireddy, MDMadhu Reddy, MDPierre Jais, MDSakis Themistoclakis, MDAntonio Dello Russo, MDMichela Casella, MDGemma Pelargonio, MDMaria Lucia Narducci, MDRobert Schweikert, MDPetr Neuzil, MDJavier Sanchez, MDRodney Horton, MDSalwa Beheiry, RNRichard Hongo, MDSteven Hao, MDAntonio Rossillo, MDGiovanni Forleo, MDClaudio Tondo, MDJ. David Burkhardt, MDMichel Haissaguerre, MDAndrea Natale, MD


    Circulation is available at


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