Atrial Fibrillation Ablation Compared to Rate Control Strategy in Patients With Recently Diagnosed Impaired Left Ventricular Function: a Multicenter, Randomized Controlled Trial

Atrial fibrillation (AF) is the most common arrhythmia among the general population. Its prevalence increases with advanced age but also with the presence of structural heart disease. In particular patients suffering from congestive heart failure (CHF) with low left ventricular (LV) ejection fraction present a significantly increased risk of developing AF and its detrimental hemodynamic effects, due to the loss of atrial contraction, and fast and irregular beats, are an even more relevant compared to patients without CHF.

In CHF patients rate control is the most widely used strategy to manage AF; in fact, it has proved non-inferior to rhythm control strategies concerning survival rates . However, adequate ventricular rate is difficult to achieve; moreover, by rate control strategy, the detrimental hemodynamic effects of AF persist, leading to a further impair in LV function, cardiac output, and symptoms. This frequently leads to the fact that, despite optimal medical therapy (OMT) for at least 3 months, the patients require implantable cardioverter defibrillator (ICD), and, in case of poor rate control AV node ablation with resynchronization therapy (CRT). The latter, however, infer pacemaker (PM)-dependence, and relate to a not negligible risk of cardiac rhythm device peri-implantation and long-term complications (infections, leads failure).

On the other side rhythm control may represent an option. In the general population, in fact, recent evidences suggest an advantage over rate control concerning survival, quality of life and thromboembolic events. The main limitation, however, stands in how to achieve rhythm control: antiarrhythmic therapy has several side effects (amiodarone, in fact the only recommended drug, is thrived by frequent adverse events) and transcatheter AF ablation has been assessed only in modest sample size studies.

Available literature focusing on a comparison between different management strategies in patients with CHF and AF is limited. A small randomized study compared pulmonary veins (PVs) isolation to AV node ablation and biventricular PM implantation, showing improved 6-month outcome, defined by a composite end point of LV ejection fraction, 6-minutes walking distance and Minnesota Living with Heart Failure (MLWHF) questionnaire, in patients treated by PVs isolation. However, only 81 patients were enrolled in this short-term study, and no hard end point tested. More recently, and actually ongoing, the AATAC-AF study, is comparing amiodarone and catheter ablation in patients with chronic AF and an implantable device (biventricular PM or ICD). Also in this case, the preliminary results support an improved 24 month outcome, in terms of sinus rhythm (SR) achievement, quality of life and LV function, in patients undergoing AF ablation .

In addition to these direct comparisons, other indirect evidences support catheter ablation rhythm control . In a recent meta-analysis, PVs isolation, linear lesions and ablation of fragmented potentials in left atrium, although with a relatively high need for repeated procedures, have proven not only to be safe but also effective in improving symptoms (related to both CHF and AF), LV function and maintaining SR. In fact, in this analysis, 60% of the patients with a left ventricular function below 35% at baseline improved to a value above this limit following AF ablation.