Novel Cardiac CT Method for Identifying the Atrioventricular Conduction Axis via Anatomical Landmarks.
Academic Article
Overview
abstract
BACKGROUND: Understanding the conduction axis location aids in avoiding iatrogenic damage and guiding targeted heart rhythm therapy. OBJECTIVE: Cardiac structures visible with clinical imaging have been demonstrated to correlate with variability in the conduction system course. We aimed to standardize and assess the reproducibility of predicting the location of the atrioventricular conduction axis by cardiac computed tomographic. METHODS: We evaluated 477 patients with acquired aortic valvar disease by cardiac computed tomography to assess variability in cardiac structures established to relate to the conduction system. We standardized three points (Points A-C) to estimate the course from the atrioventricular node, to the non-branching bundle and left bundle branch origin, and further compared this to measures of variability in the aortic root and membranous septum. RESULTS: The mean distance between the aortic valvar virtual basal ring and Points A, B, and C were 9.5±3.5 (0.3-20.1) mm, 5.0±2.6 (-1.7-15.9) mm, and 2.8 ± 2.4 (-5.2-12.0) mm, respectively. The midpoint of the membranous septum deviated posteriorly a median of -4.4 (IQR -12.4-+3.0) degrees relative to the commissure between the right and non-coronary leaflets. Intraclass coefficients for both intra- and inter-observer variability for all measured points were excellent (≥0.78). CONCLUSIONS: These findings further infer the intimate, yet highly variable relationship between the conduction axis and aortic root. This reproducible and standardized approach requires validation in patient populations requiring accurate identification of the atrioventricular components of the conduction axis, and may serve as a non-invasive means for estimating its location.
