We have read with great interest the report by Roten et al regarding predictors of atrioventricular (AV) conduction impairment after transcatheter aortic valve implantation with the CoreValve prosthesis (Medtronic, Inc., Minneapolis, Minnesota). We have published our early experience with this prosthesis and recently performed electrophysiologic studies in some pacemaker-free patients immediately before and after valve implantation. An electrode was placed on the His bundle during valve implantation, and data were continuously recorded during the procedure. We agree that the type of AV block is intra- or infrahisian; in fact, our group has published for the first time a report of intrahisian AV block in a patient who underwent percutaneous CoreValve prosthesis implantation. However, we are extremely surprised by the high AV conduction recovery rate, taking in account that infrahisian blocks are usually permanent. In our series with the first 50 patients who underwent percutaneous implantation of the CoreValve prosthesis, pacemaker implantation was needed in 22 patients (44%), 20 patients because of complete AV block and 2 patients because of first-degree AV block with newly developed left bundle branch block. Of the 20 patients, considering a subgroup of 15 patients who were discharged alive from the hospital and after a median follow-up period of 435 days, only 2 patients recovered cardiac rhythm, and the remaining patients had escape rhythm, with a mean heart rate of 28 beats/min. Compared with Roten et al’s study, these differences may be explained in part by technical aspects of the procedure and differences in the prostheses implanted, as in our hospital, we implant only CoreValve prostheses. Considering our data and those of Roten et al (median follow-up period 79 days) together, we can speculate that AV conduction impairment seems to be slowly progressive over time, which supports early pacemaker implantation in patients who develop second or third AV block despite detecting recovery of AV block.