An analysis of randomised controlled trials (RCTs) has found catheter ablation reduces mortality and heart failure hospitalisations in patients with atrial fibrillation (AF) and heart failure. Findings of the study were published in the journal Europace.
Carrying out a meta-analysis of RCTs that evaluated effects of AF ablation and heart disease, Florentina A Simader (National Heart and Lung Institute, Imperial College London, London, UK) and colleagues considered all randomised studies and reported on cardiovascular outcomes. Observational studies were deemed ineligible.
Affecting 3% of adults, AF is associated with death, stroke, the development of heart failure and subsequent hospitalisation. If diagnosed concurrently, AF and heart failure pose a much more serious prognosis. Until recently evidence showing the effects of ablation on patients with heart disease was slight and had been observed in un-blinded studies, providing controversial links between symptom improvement and treatment. The European Society of Cardiology (ESC) recommends AF ablation to patients with heart failure in the context of tachycardiomyopathy to reverse left ventricular dysfunction.
Recent trials have found that earlier ablation, in comparison to the trialling of medical therapy, can lead to better outcomes and prevent adverse remodelling occurring.
The authors of the study systematically identified trials which compared catheter ablation to medical therapy in patients with heart failure and AF. The prespecified primary endpoint was all-cause mortality in trials that included two or more years of follow-up, the secondary endpoint being heart failure hospitalisation.
Eight trials including 1,390 patients met inclusion criteria for the study. Three trials (RAFT-AF, CASTLE-AF and AATAC) however met the primary follow-up criteria, which enrolled 977 patients. Of this group, 425 were randomised to ablation and 482 to medical therapy. Authors of the study independently abstracted data from the trials and analysed efficacy on an intention-to-treat basis.
Of the three qualifying trials, catheter ablation was observed to significantly reduce all-cause mortality (relative risk [RR] 0.61; 95% confidence interval [CI] 0.44‒0.84; p=0.003) with low-heterogeneity (12.5%) compared with medical therapy. Catheter ablation also reduced heart failure hospitalisations (RR 0.60; 95% CI 0.49‒0.74; p < 0.001) with no heterogeneity (0%) when compared to medical therapy.
The authors reveal that all-cause mortality was reduced by 39% and hospitalisation by 40% when patients received early catheter ablation for AF and heart disease. In all trials included in the study, pulmonary vein isolation was the base procedure, although linear and complex fractionated atrial electrogram ablation was offered on a case by case basis.
In the discussion of their findings, Simader et al emphasise the “magnitude of benefit” ablation has in improving cardiovascular outcomes in patients. However the authors do point to various limitations, noting patients lost to follow-up post-randomisation, and early trial termination on grounds of “apparent futility”, that may have potentially influenced the true average effect of their analysis.
The authors conclude however that despite limitations, trials have been performed in multiple settings, proving demonstrable generalisability: “Our findings demonstrate compelling RCT evidence of survival and hospitalisation benefit with AF ablation in heart failure”.
