Atrial Fibrillation in Patients with Cardiac Resynchronization Therapy: Clinical Management and Outcome

Atrial fibrillation (AF) and heart failure (HF) are two emerging epidemics in the cardiovascular field and are strictly inter-related since may directly predispose to each other. Cardiac resynchronization therapy (CRT) has emerged as an important therapeutic option for selected HF patients with LV dysfunction and ventricular dyssynchrony. However almost all RCTs demonstrated the CRT effectiveness in patients in sinus rhythm (SR), including permanent AF among the exclusion criteria. In patients with paroxysmal or persistent AF strategies for rhythm control can be applied, but usually with limited efficacy. Furthermore, rhythm control strategy did not result superior to rate-control in patients with heart failure. AF ablation in HF patients is usually performed only in selected centres. In patients with permanent or long-standing AF and a CRT device the option of AVN ablation offers the advantage of allowing >95% biventricular pacing. AF implies a harmful increase in thromboembolic risk. Detection of AF in patients treated with a CRT device is enhanced by device diagnostic capabilities, that allow detection of episodes of atrial tachyarrythmias, including silent AF. In these cases decision making on appropriate antithrombotic prophy/laxis has to consider clinical risk stratification, usually applying CHADS₂ and CHA₂DS₂VASc scores. In summary, in order to maximise outcome, AF in patients with CRT prompts the need to appropriately decide on antithromboembolic prophylaxis (according to risk stratifications), as well as on rate and/or rhythm control strategies, with the aim to allow constant biventricular pacing. In this perspective, AVN ablation has an important role since by inducing pace-maker dependency guarantees continuous biventricular pacing.