title: Inverse Relationship Between Membranous Septal Length and the Risk of Atrioventricular Block in Patients Undergoing Transcatheter Aortic Valve Implantation.
abstract: OBJECTIVE
  This study sought to examine whether imaging of the atrioventricular (AV) membranous septum (MS) by computed tomography (CT) can be used to identify patient-specific anatomic risk of high-degree AV block and permanent pacemaker (PPM) implantation before transcatheter aortic valve implantation (TAVI) with self-expandable valves.
  
  
  BACKGROUND
  MS length represents an anatomic surrogate of the distance between the aortic annulus and the bundle of His and may therefore be inversely related to the risk of conduction system abnormalities after TAVI.
  
  
  METHODS
  Seventy-three consecutive patients with severe aortic stenosis underwent contrast-enhanced CT before TAVI. The aortic annulus, aortic valve, and AV junction were assessed, and MS length was measured in the coronal view.
  
  
  RESULTS
  In 13 patients (18%), high-degree AV block developed, and 21 patients (29%) received a PPM. Multivariable logistic regression analysis revealed MS length as the most powerful pre-procedural independent predictor of high-degree AV block (odds ratio [OR]: 1.35, 95% confidence interval [CI]: 1.1 to 1.7, p = 0.01) and PPM implantation (OR: 1.43, 95% CI: 1.1 to 1.8, p = 0.002). When taking into account pre- and post-procedural parameters, the difference between MS length and implantation depth emerged as the most powerful independent predictor of high-degree AV block (OR: 1.4, 95% CI: 1.2 to 1.7, p < 0.001), whereas the difference between MS length and implantation depth and calcification in the basal septum were the most powerful independent predictors of PPM implantation (OR: 1.39, 95% CI: 1.2 to 1.7, p < 0.001 and OR: 4.9, 95% CI: 1.2 to 20.5, p = 0.03; respectively).
  
  
  CONCLUSIONS
  Short MS, insufficient difference between MS length and implantation depth, and the presence of calcification in the basal septum, factors that may all facilitate mechanical compression of the conduction tissue by the implanted valve, predict conduction abnormalities after TAVI with self-expandable valves. CT assessment of membranous septal anatomy provides unique pre-procedural information about the patient-specific propensity for the risk of AV block.
authors: Heart Institute, Sheba Medical Center, Tel Hashomer, Sackler Faculty of Medicine, Tel-Aviv University, Tel Aviv, Israel; Department of Diagnostic Imaging, Sheba Medical Center, Tel Hashomer, Sackler Faculty of Medicine, Tel-Aviv University, Tel Aviv, Israel. Electronic address: hamdashraf@gmail.com.
authors: Ashraf
authors: A
authors: Hamdan
authors: Heart Institute, Sheba Medical Center, Tel Hashomer, Sackler Faculty of Medicine, Tel-Aviv University, Tel Aviv, Israel.
authors: Victor
authors: V
authors: Guetta
authors: Heart Institute, Sheba Medical Center, Tel Hashomer, Sackler Faculty of Medicine, Tel-Aviv University, Tel Aviv, Israel.
authors: Robert
authors: R
authors: Klempfner
authors: Department of Diagnostic Imaging, Sheba Medical Center, Tel Hashomer, Sackler Faculty of Medicine, Tel-Aviv University, Tel Aviv, Israel.
authors: Eli
authors: E
authors: Konen
authors: Department of Cardiac Surgery, Sheba Medical Center, Tel Hashomer, Sackler Faculty of Medicine, Tel-Aviv University, Tel Aviv, Israel.
authors: Ehud
authors: E
authors: Raanani
authors: Heart Institute, Sheba Medical Center, Tel Hashomer, Sackler Faculty of Medicine, Tel-Aviv University, Tel Aviv, Israel.
authors: Michael
authors: M
authors: Glikson
authors: Department of Diagnostic Imaging, Sheba Medical Center, Tel Hashomer, Sackler Faculty of Medicine, Tel-Aviv University, Tel Aviv, Israel.
authors: Orly
authors: O
authors: Goitein
authors: Heart Institute, Sheba Medical Center, Tel Hashomer, Sackler Faculty of Medicine, Tel-Aviv University, Tel Aviv, Israel.
authors: Amit
authors: A
authors: Segev
authors: Heart Institute, Sheba Medical Center, Tel Hashomer, Sackler Faculty of Medicine, Tel-Aviv University, Tel Aviv, Israel.
authors: Israel
authors: I
authors: Barbash
authors: Heart Institute, Sheba Medical Center, Tel Hashomer, Sackler Faculty of Medicine, Tel-Aviv University, Tel Aviv, Israel.
authors: Paul
authors: P
authors: Fefer
authors: Department of Cardiac Surgery, Sheba Medical Center, Tel Hashomer, Sackler Faculty of Medicine, Tel-Aviv University, Tel Aviv, Israel.
authors: Dan
authors: D
authors: Spiegelstein
authors: Heart Institute, Sheba Medical Center, Tel Hashomer, Sackler Faculty of Medicine, Tel-Aviv University, Tel Aviv, Israel.
authors: Ilan
authors: I
authors: Goldenberg
authors: Heart Institute, Sheba Medical Center, Tel Hashomer, Sackler Faculty of Medicine, Tel-Aviv University, Tel Aviv, Israel.
authors: Ehud
authors: E
authors: Schwammenthal
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001021:Aortic Valve / Q000000981:diagnostic imaging* / Q000503:physiopathology; D001024:Aortic Valve Stenosis / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000628:therapy*; D054537:Atrioventricular Block / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology / Q000628:therapy; D006328:Cardiac Catheterization / Q000009:adverse effects* / Q000295:instrumentation; D002304:Cardiac Pacing, Artificial; D005260:Female; D006346:Heart Septum / Q000000981:diagnostic imaging*; D006350:Heart Valve Prosthesis; D019918:Heart Valve Prosthesis Implantation / Q000009:adverse effects* / Q000295:instrumentation; D006801:Humans; D016015:Logistic Models; D008297:Male; D061330:Multidetector Computed Tomography; D015999:Multivariate Analysis; D016017:Odds Ratio; D011237:Predictive Value of Tests; D018570:Risk Assessment; D012307:Risk Factors; D012720:Severity of Illness Index; D016896:Treatment Outcome
keywords: CT; TAVI; atrioventricular block; implantation depth; membranous septum; permanent pacemaker