Clinical Pearls & Morning Reports
Published January 31, 2018
Catheter ablation is a well-established option for symptomatic atrial fibrillation that is resistant to drug therapy in patients with otherwise normal cardiac function, and various studies have shown that ablation is associated with positive outcomes in patients with heart failure. Nevertheless, the effectiveness of catheter ablation in improving rates of hard primary end points such as death or the progression of heart failure has not been tested in large, randomized, controlled trials, and guidelines provide no clear consensus regarding the best management approach. Marrouche et al. initiated the Catheter Ablation versus Standard Conventional Therapy in Patients with Left Ventricular Dysfunction and Atrial Fibrillation (CASTLE-AF) trial to address this issue. Read the NEJM Original Article here.
Q: What were the selection criteria for the CASTLE-AF trial?
A: Patients with heart failure and a history of symptomatic atrial fibrillation were screened. To be enrolled in the trial, patients had to have paroxysmal or persistent atrial fibrillation; an absence of response to, unacceptable side effects from, or unwillingness to take antiarrhythmic drugs; and New York Heart Association (NYHA) class II, III, or IV heart failure and a left ventricular ejection fraction (LVEF) of 35% or less.
Q: How was recurrent atrial fibrillation detected among participants in the CASTLE-AF trial?
A: To facilitate detection of recurrence of atrial fibrillation, all the patients were required to have an implanted cardioverter–defibrillator (ICD) device or a cardiac resynchronization therapy defibrillator (CRT-D) with automatic daily remote-monitoring capabilities.
A: In the CASTLE-AF trial, the authors found that the use of ablation for atrial fibrillation in patients with heart failure was associated with a significantly lower rate of a composite of death and hospitalization for heart failure than medical therapy. The composite primary end point — death or hospitalization for worsening heart failure — occurred in significantly fewer patients in the ablation group than in the medical-therapy group (51 patients [28.5%] vs. 82 patients [44.6%]; P=0.006 by the log-rank test). The trial included patients with both paroxysmal and persistent atrial fibrillation and found that both groups benefited from catheter ablation.
A: All secondary analyses were considered to be exploratory and were not adjusted for multiple testing. There were 24 deaths in the ablation group and 46 deaths in the medical-therapy group, with rates of 13.4% and 25.0%, respectively. There were 37 patients with heart failure–related admissions in the ablation group and 66 patients in the medical-therapy group, with rates of 20.7% and 35.9%, respectively. There were 20 cardiovascular deaths (11.2%) in the ablation group and 41 (22.3%) in the medical-therapy group. The median absolute increase in LVEF from baseline to the 60-month follow-up visit was 8.0% (interquartile range, 2.2 to 19.1) in the ablation group and was 0.2% (−3.0 to 16.1) in the medical-therapy group. On the basis of the data extracted from the memory of the implanted devices, 63.1% of the patients in the ablation group and 21.7% in the medical-therapy group were in sinus rhythm at the 60-month follow-up visit and had not had recurrence of atrial fibrillation since the previous follow-up visit (typically at 48 months).