Anatomical variations and clinical significance of atrioventricular bundle of His: A concise literature review

Abstract

Background: The cardiac conduction system (CCS) consists of the sinoatrial node, atrioventricular node, the atrioventricular bundle of His (HB), and its branches which terminate as subendocardial branches, also known as the Purkinje fibers. Each element of the CCS can exhibit anatomical variations. Objective: This review aims to summarize the current knowledge on anatomical variations of HB and its branches, together with the clinical implications of those variations. Methods: The literature search included medical articles published starting from 2015. For the analysis, 60 papers were involved. The articles came from PubMed, Google Scholar, Frontiers, Science Direct, and Web of Science. Results: The HB relationship to the right fibrous trigone and membranous part of the interventricular septum can differ among individuals. Variations also include the ramification, i.e., the number of branches and the width, length, and even thickness of individual branches. In particular, HB and its left branch show the most remarkable diversity in the course, length, and position. The right branch of HB, which for most of its course runs in an unbranched fashion, is much less variable. Conclusions: Knowledge of CCS anatomical variations can be essential to understand cardiac electrophysiology better. With this knowledge, the bundle-branch pacing method can be used in patients with cardiac arrhythmias.

Keywords

• Conducting system of heart
• Atrioventricular (His) bundle
• His bundle pacing
• Left/right bundle branch
• Subendocardial branches (Purkinje fibers)