Anatomical Predictors of Pacemaker Dependency after Transcatheter Aortic Valve Replacement

Background - Conduction disturbances after transcatheter aortic valve replacement (TAVR) are often transient. Limited data exist on anatomic factors predisposing to PM dependency after TAVR. We sought to assess the rate and the possible predictors of pacemaker (PM) dependency after transcatheter aortic valve replacement (TAVR). Methods - Consecutive patients undergoing PM implantation up to 30-day after TAVR between May 2014 and September 2019 were included. Baseline electrocardiographic, computed tomography and procedural characteristics were collected, including valve implantation depth (ID) and membranous septum (MS) length, an anatomic surrogate of the distance between the aortic annulus and the His bundle. PM dependency at 30-day and 1-year and all-cause mortality during follow up were evaluated. Results - Of 728 TAVR patients, 112 (53.5% males, median age 81) underwent PM implantation after TAVR. Of these, 44.6% (50/112) were PM-dependent at 30-day, 46.7% (36/77) at 1-year. By multivariate analysis, independent predictors of 30-day PM dependency included left ventricular outflow tract (LVOT) calcifications under the left coronary cusp (LCC) (OR: 5.69, 95%CI: 1.45-22.31, p=0.013) and a difference between MS length and ID (ΔMSID) ≥3 mm (OR: 7.58, 95%CI: 2.07-27.78, p=0.002). Conversely, MS length and ID alone were not associated with PM dependency (OR: 0.79, 95%CI: 0.60-1.05, p=0.11 and OR: 1.11, 95%CI: 0.99-1.24, p=0.08). At a median follow-up of 28.1 [11.7-48.6] months, PM-dependent patients did not show a worse survival (p=0.26). Conclusions - Less than half of the patients undergoing PM implantation after TAVR are PM-dependent at mid-term follow-up. ΔMSID ≥3mm and presence of LVOT calcifications under the LCC, but not MS length nor ID alone, are predictive of long-term PM dependency after TAVR, thus influencing device selection and programming.