Catheter‐induced right bundle branch block: Practical implications for the cardiac electrophysiologist

Abstract The right bundle branch (RBB), due to its endocardial course, is susceptible to traumatic block caused by “bumping” during right‐heart catheterization. In the era of cardiac electrophysiology, catheter‐induced RBB block (CI‐RBBB) has become a common phenomenon observed during electrophysiological studies and catheter ablation procedures. While typically transient, it may persist for the entire procedure time. Compared to pre‐existing RBBB, the transient nature of CI‐RBBB allows for comparative analysis relative to the baseline rhythm. Furthermore, unlike functional RBBB, it occurs at similar heart rates, making the comparison of conduction intervals more reliable. While CI‐RBBB can provide valuable diagnostic information in various conditions, it is often overlooked by cardiac electrophysiologists. Though it is usually a benign and self‐limiting conduction defect, it may occasionally lead to diagnostic difficulties, pitfalls, or undesired consequences. Avoidance of CI‐RBBB is advised in the presence of baseline complete left bundle branch block and when approaching arrhythmic substrates linked to the right His‐Purkinje‐System, such as fasciculo‐ventricular pathways, bundle branch reentry, and right‐Purkinje focal ventricular arrhythmias. This article aims to provide a comprehensive practical review of the electrophysiological phenomena related to CI‐RBBB and its impact on the intrinsic conduction system and various arrhythmic substrates.