Effects of atrial fibrillation ablation on arrhythmia burden and ventricular function in end-stage heart failure: Lessons from CASTLE-HTx

Abstract

Aims: The CASTLE-HTx trial showed the benefit of atrial fibrillation (AF) ablation compared to medical therapy in decreasing mortality, need for left ventricular assist device implantation or heart transplantation (HTx) in patients with end-stage heart failure (HF). Herein we describe the effects of catheter ablation on AF burden, arrhythmia recurrences, and ventricular function in end-stage HF.

Methods and results: The CASTLE-HTx protocol randomized 194 patients in end-stage HF with AF to catheter ablation and medical therapy or medical therapy alone. AF burden, left ventricular ejection fraction (LVEF), and type of AF were assessed at baseline and at each follow-up visit. Overall, 97 patients received ablation; 66 patients (68%) underwent pulmonary vein isolation (PVI) and 31 patients (32%) were treated with PVI and additional ablation. Electroanatomic mapping showed the extent of left atrial low voltage (cardiomyopathy) >10% in 31 (31.9%) patients. At 12 months post-ablation, persistent AF was present in 31/89 patients (34.8%), which was significantly less frequent compared to baseline (p = 0.0001). Median AF burden reduction was 36.3 (interquartile range 13.6-63.3) percentage points at 12 months and LVEF improved from 29.2 ± 6.2% to 39.1 ± 8.3% (p < 0.001) following ablation. AF burden reduction <50% was significantly associated with LVEF improvement ≥5% at 12 months after ablation (p = 0.017).

Conclusion: Atrial fibrillation ablation in end-stage HF leads to a substantial decrease in AF burden, a regression from persistent to paroxysmal AF and notably improved LVEF. Favourable ablation outcomes were observed in patients regardless of the presence or absence of signs indicating left atrial cardiomyopathy.

Keywords: Atrial fibrillation; Catheter ablation; Heart failure; Heart transplantation; Left ventricular assist device.

Figure 1

Improvement of left ventricular ejection fraction (A) and atrial fibrillation burden (B) for patients treated with ablation and not treated with ablation. The data from patients who did not receive ablation were obtained and adjusted from. I bars indicate the standard deviation.

Figure 2

Atrial fibrillation (AF) regression from persistent to paroxysmal AF or sinus rhythm (SR). The type of AF before and after catheter ablation irrespective of the ablation strategy is shown at 12 months after ablation. Patients who received catheter ablation and survived 12 months following ablation without a primary endpoint event (composite of death from any cause, left ventricular assist device implantation or heart transplantation) were analysed.