Effects of Preferential Left Ventricular Pacing on Ventriculoarterial Coupling and Clinical Course of Heart Failure

Study hypothesis is that preferential left ventricular (LV) pacing, delivered by means of the AdaptivCRT® algorithm and in conjunction with automated V-V delay adjustments, will lead to improvements over standard biventricular pacing (BVP) in the function of all cardiac chambers, reduce arrhythmic burden, improve ventricular-arterial coupling (VAC), and patient functional status. It would be interesting to study what changes in right-side VAC (RVAC) can be appreciated with the activation of the preferential LV pacing algorithm and how they relate to each other, i.e. whether LV is driven towards maximizing output whilst RV shifts to optimizing energy efficiency. READAPT is a single-center, prospective, randomized trial of heart failure patients eligible for CRT according to current European heart failure guidelines. Informed written consent is required from all study participants. Adult (aged 18-80 years old), consenting patients with any cardiomyopathy type, diagnosed at least 6 months prior (to exclude recent myocarditis cases that may remit and confound outcomes), on optimal medical therapy for at least 3 months, and an existing I/IIa indication for a cardiac resynchronization therapy - defibrillator (CRT-D) device will be enrolled and randomized into 2 groups, one receiving standard CRT (Group 1 - G1), and one with activation of the preferential LV pacing algorithm (Group 2 - G2). Enrollment date will amount to the baseline assessment date, with device implantation occurring preferably within 48 hours. READAPT will include patients with both new CRT-D implantation and an upgrade from an existing defibrillator or pacemaker with no prior left ventricular lead placement.