Conduction System Pacing Versus Biventricular Pacing For Cardiac Resynchronization - Preliminary Electrocardiographic Results

Cardiac resynchronization therapy with biventricular pacing (BiV) is the cornerstone treatment for heart failure patients with ventricular dyssynchrony. Recently, the conduction system pacing (CSP) has being introduced as a possible alternative. We hypothesized that CSP could produce a more complete electrical resynchronization compared to conventional BIV pacing. To trace the spreading of myocardial depolarization, we assessed equivalent dipole (ED) trajectories utilizing the BEM method with a tailored human torso from the high resolution 12-lead ECG before and after device implantation in 17 patients included in our ongoing randomized CSP-SYNC study. We observed a similar relative shortening of the QRS duration (0,23 in CSP and 0,25 in BiV) and relative ED trajectory length (0,16 in CSP and 0,20 in BiV). However, a significant change of ED trajectory direction occurred after the therapy. In BiV pacing, the trajectory direction shifted more towards the base of the heart, but more apically in CSP, mimicking normal heart depolarization Resynchronization with CSP seems to restore more physiological depolarization compared to BiV pacing. The assessment of the ED trajectories provides additional insight into the electrical heart remodelling after the therapy.