The evolution of conduction system pacing and gaps in understanding.

The field of cardiac pacing has changed dramatically since the first pacemakers were implanted in the 1950s.1 Over the ensuing decades, advancements in pacing technology have yielded longer battery life, smaller devices, sturdier leads, and more sophisticated pacemaker programming. Cardiac resynchronization therapy (CRT) represented a significant revolution in pacing approach, with the goal of correcting interventricular dyssynchrony through biventricular pacing. More recently, conduction system pacing (CSP) has emerged as a means to deliver even more physiological activation through direct engagement of the conduction system. The enthusiasm for CSP, driven primarily by investigator-initiated studies, has led to a rapid evolution in our understanding of conduction system physiology and represents a contemporary paradigm shift in our approach to treating patients with bradyarrhythmias and heart failure. The goal of this review is to provide a brief overview of the progression of CSP over time and to highlight key gaps in our understanding that need to be resolved prior to moving forward (Graphical Abstract).