Left Bundle Branch Area Pacing Generates More Physiological Ventricular Activation Sequences than Right Ventricular Pacing

Left bundle branch area pacing (LBBAP) has been proposed as a novel physiological pacing modality to overcome ventricular dyssynchrony reported in bradycardic patients who undergo conventional right ventricular pacing (RVP). The standard non-invasive measure of depolarization synchrony is the QRS duration. However, a deeper understanding of not only the activation time but also the activation sequence is required to evaluate the effects of RVP and LBBAP in bradycardic patients. This study aimed to characterize and compare the ventricular activation sequences obtained from both pacing techniques, LBBAP and RVP, by analyzing the standard 12-lead ECGs of bradycardic patients with physiological conduction. 22 RVP and 42 LBBAP ECG recordings were collected before and after pacemaker implantation. High (HF) and low (LF) frequency-based methods for QRS complex analysis were used and the precordial activation sequence and activation delay (pAD) were estimated. Results showed more physiological activation sequences after LBBAP than after RVP, with lower pAD (p<0.01) after LBBAP [HF: 12(-2,15) vs 29(6,56); LF: 9(-25,13) vs 31(17,38)). The proposed ECG methodology could be used in clinical practice to map more physiological pacing targets in pacemaker implantation.