Abstract Funding Acknowledgements Type of funding sources: None. Introduction One of the most frequent intraprocedural complication of patients undergoing transcatheter aortic valve replacement (TAVR) is high degree atrioventricular block (HDAVB). The incidence varies from 5-20% depending on the type of valve, previous surgical valve replacement (SVR) and basal conduction disturbances. Purpose The purpose of this study was to evaluate the incidence of intraprocedural HDAVB in patients undergoing TAVR in native valves versus patients with previous SVR derived for valve-in-valve TAVR (VIV-TAVR). Methods Data was collected from all the patients undergoing TAVI in a single center from December 2007 to July 2019. The primary endpoint was to compare the incidence of HDAVB in patients undergoing TAVR versus patients undergoing VIV-TAVI. The secondary endpoint was to describe the differences in the baseline characteristics of patients that presented with HDAVB vs patients without HDAVB. Results A total of 661 patients were derived for TAVR and separated into 2 groups for analysis. 596 patients with native valves treated with TAVR and 65 patients with previous SVR treated with VIV-TAVI. The primary outcome was present in 87 patients (14,6%) in the TAVR group vs 1 patient (1,54%) in the VIV-TAVR group (p: 0,0033). Patients with HDAVB (n = 88) had a mean age of 83,1 ± 6,26 years. The baseline EKG showed a conduction disturbance in 47,6% of the cases (50% of right bundle branch block; 21,8% of first degree AVB; 15,09% of left bundle branch block and 35,85% of left anterior fascicular block). A new permanent pacemaker was implanted in 77 (87,5%) patients. Patients without HDAVB (n = 573) had a mean age of 82,5 ± 6,14 years. The baseline EKG showed a conduction disturbance in 28,91% of the cases (22,73% of Right bundle branch block; 25,68% of first degree AVB; 31,70% of left bundle branch block and 21,25% of left anterior fascicular block). A new permanent pacemaker was implanted in 59 (10,30%) patients. Conclusions There is a very low incidence of intraprocedural HDAVB in patients undergoing VIV-TAVR compared to the rest of TAVR procedures (1,54% vs 14,6% p:0,0033). Moreover, the only predictors that associated with the development of HDAVB where previous right bundle branch block and left anterior fasicular hemiblock. The development of intraprocedural HDAVB is associated with the need of a new permanent pacemaker. Table 1: Basal CharacteristicsNo HDAVBHDAVBp VALUEAge, yrs82,683,10,453Basal conduction disturbance28,91 %47,62 %<0,0001PPM implantation10,3 %85,2 %<0,0001Basal characteristicsAbstract Figure. Clinical characteristics by groups