RT Journal Article SR Electronic T1 Variations in rotation of the aortic root and membranous septum with implications for transcatheter valve implantation JF Heart JO Heart FD BMJ Publishing Group Ltd and British Cardiovascular Society SP 999 OP 1005 DO 10.1136/heartjnl-2017-312390 VO 104 IS 12 A1 Justin T Tretter A1 Shumpei Mori A1 Farhood Saremi A1 Sathish Chikkabyrappa A1 Kristen Thomas A1 Fang Bu A1 Rohit S Loomba A1 Tarek Alsaied A1 Diane E Spicer A1 Robert H Anderson YR 2018 UL http://heart.bmj.com/content/104/12/999.abstract AB Objective It is intuitive to suggest that knowledge of the variation in the anatomy of the aortic root may influence the outcomes of transcatheter implantation of the aortic valve (TAVI). We have now assessed such variation.Methods We used 26 specimens of normal hearts and 78 CT data sets of adults with a mean age of 64±15 years to measure the dimensions of the membranous septum and to assess any influence played by rotation of the aortic root, inferring the relationship to the atrioventricular conduction axis.Results The aortic root was positioned centrally in the majority of both cohorts, although with significant variability. For the cadaveric hearts, 14 roots were central (54%), 4 clockwise-rotated (15%) and 8 counterclockwise-rotated (31%). In the adult CT cohort, 44 were central (56%), 21 clockwise-rotated (27%) and 13 counterclockwise-rotated (17%). A mean angle of 15.5° was measured relative to the right fibrous trigone in the adult CT cohort, with a range of −32° to 44.7°. The dimensions of the membranous septum were independent of rotation. Fibrous continuity between the membranous septum and the right fibrous trigone increased with counterclockwise to clockwise rotation, implying variation in the relationship to the atrioventricular conduction axis.Conclusions The central fibrous body is wider, providing greater fibrous support, in the setting of clockwise rotation of the aortic root. Individuals with this pattern may be more vulnerable to conduction damage following TAVI. Knowledge of such variation may prove invaluable for risk stratification.