The Electrocardiogram and New Methods for Measuring Electrical Synchrony in Cardiac Resynchronization Therapy and Conduction System Stimulation

The different forms of stimulation have been accompanied throughout their evolution by various methods of assessing electrical synchrony, the most widely used being the 12-lead electrocardiogram. However, the emergence of new paradigms and the breakdown of various concepts that have been entrenched for years have allowed the emergence of new evaluation methods. The objective of this review is to explore the utilities of the ECG and new tools for measuring electrical synchrony that accompany cardiac resynchronization therapy (CRT) and physiological stimulation. This includes their role in preselection, during the chosen procedure, and in post-procedure optimization for the follow-up of patients with heart failure (HF) (to electrically resynchronize them) and for patients with chronic pacing (to avoid desynchronization).