Electrophysiology & Devices

In left bundle branch block or right ventricular apical pacing, ventricular activation no longer proceeds through the rapid His-Purkinje network but instead spreads slowly, cell-to-cell, from a single point of earliest activation. This produces mechanical dyssynchrony, in which some segments contract before others are ready, wasting energy, reducing stroke volume, and over time driving adverse remodeling — sometimes called pacing-induced cardiomyopathy when caused by chronic right ventricular pacing. Cardiac resynchronization therapy restores near-simultaneous activation of the septum and lateral wall by pacing both (or by pacing the conduction system directly), improving coordinated contraction and promoting reverse remodeling.