Author + information
- Received February 6, 2015
- Accepted February 12, 2015
- Published online May 1, 2015.
- Anna S. Petronio, MD∗∗ (, )
- Jan-Malte Sinning, MD†,
- Nicolas Van Mieghem, MD‡,
- Giulio Zucchelli, MD, PhD∗,
- Georg Nickenig, MD†,
- Raffi Bekeredjian, MD, PhD§,
- Johan Bosmans, MD, PhD‖,
- Francesco Bedogni, MD¶,
- Marian Branny, MD#,
- Karl Stangl, MD∗∗,
- Jan Kovac, MD††,
- Molly Schiltgen, MS‡‡,
- Stacia Kraus, MPH§§ and
- Peter de Jaegere, MD, PhD†
- ∗Cardiothoracic and Vascular Department, Azienda Ospedaliero Universitaria Pisana, Pisa, Italy
- †Department of Medicine II, Universitätsklinikum Bonn, Bonn, Germany
- ‡Department of Cardiology, Thoraxcenter, Erasmus Medical Center, Rotterdam, the Netherlands
- §Department of Cardiology, Universitätsklinikum Heidelberg, Heidelberg, Germany
- ‖Department of Cardiology, University Hospital Antwerp, Antwerp, Belgium
- ¶Department of Cardiology, Istituto Clinico S. Ambrogio, Milan, Italy
- #Department of Cardiology, Cardiocenter Hospital Podlesi, Trinec, Czech Republic
- ∗∗Department of Cardiology and Angiology, Charite, Campus Mitte-Kardiologie, Berlin, Germany
- ††Department of Cardiology, Glenfield Hospital, Leicester, United Kingdom
- ‡‡Department of Structural Heart Clinical Operations, Medtronic, Inc., Mounds View, Minnesota
- §§Department of Biostatistics, North American Sciences Associates, Inc., Minneapolis, Minnesota
- ↵∗Reprint requests and correspondence:
Prof. Anna S. Petronio, Cardiothoracic and Vascular Department, Ospedale di Cisanello, Via Paradisa 2, 56124 Pisa, Italy.
Objectives The aim of the CoreValve prospective, international, post-market ADVANCE-II study was to define the rates of conduction disturbances and permanent pacemaker implantation (PPI) after transcatheter aortic valve replacement with the Medtronic CoreValve System (Minneapolis, Minnesota) using optimized implantation techniques and application of international guidelines on cardiac pacing.
Background Conduction disturbances are a frequent complication of transcatheter aortic valve replacement. The rates of PPI in the published reports vary according to bioprosthesis type and the indications for PPI.
Methods The primary endpoint was the 30-day incidence of PPI with Class I/II indications when the Medtronic CoreValve System was implanted at an optimal depth (≤6 mm below the aortic annulus). The timing and resolution of all new-onset conduction disturbances were analyzed.
Results A total of 194 patients were treated. The overall rate of PPI for Class I/II indications was 18.2%. An optimal depth was reached in 43.2% of patients, with a nonsignificantly lower incidence of PPI in patients with depths ≤6 mm, compared with those with deeper implants (13.3% vs. 21.1%; p = 0.14). In a paired analysis, new-onset left bundle branch block and first-degree atrioventricular block occurred in 45.4% and 39.0% of patients, respectively, and resolved spontaneously within 30 days in 43.2% and 73.9%, respectively. In patients with new PPI, the rate of intrinsic sinus rhythm increased from 25.9% at 7 days to 59.3% at 30 days (p = 0.004).
Conclusions Optimal Medtronic CoreValve System deployment and adherence to international guidelines on cardiac pacing are associated with a lower rate of new PPI after transcatheter aortic valve replacement, compared with results reported in previous studies. (CoreValve Advance-II Study: Prospective International Post-Market Study [ADVANCE II]; NCT01624870)
- aortic stenosis
- conduction disturbance
- permanent pacemaker implantation
- transcatheter aortic valve replacement
Transcatheter aortic valve replacement (TAVR) is now an established and safe therapy for patients with aortic stenosis who are at high risk for surgical aortic valve replacement (1,2). Conduction disturbances (CD) requiring permanent pacemaker implantation (PPI) frequently occur following implantation of the self-expanding Medtronic CoreValve System (MCS) (Medtronic Inc., Minneapolis, Minnesota). However, the reported rate of PPI varies widely, ranging from 10% to 47% (3–7). Although improvement in operator skill has led to a consistent reduction in the occurrence of such complications, the variability in PPI rates persists. This is most likely due to varying criteria underlying pacemaker implantation decisions and lack of consensus on the treatment strategy for CD after TAVR.
The purpose of ADVANCE II (the CoreValve Prospective International Post-Market Advance II Study) was to evaluate the rate of new PPI according to Class I or II indications as recommended by the European Society of Cardiology (ESC) (8) when the MCS was optimally deployed at a depth of ≤6 mm below the aortic annulus. In addition, we assessed the rate of new-onset CD and the time course of their resolution, as well as the safety and efficacy outcomes associated with the TAVR procedure.
Patients undergoing TAVR for symptomatic aortic stenosis and treated with the MCS were prospectively enrolled after heart team evaluation. Inclusion and anatomic exclusion criteria were consistent with manufacturer recommendations. Patients with a pre-existing device that regulated heart rhythm, as well as patients with pre-existing class I or II indications for a new PPI according to the 2007 ESC guidelines were not eligible. Persistent and permanent atrial fibrillation were also exclusion criteria as these conditions preclude accurate assessment of new-onset conduction disturbances.
All patients underwent TAVR with CoreValve and the 18-F delivery system with the AccuTrak Stability Layer as previously described (1). Valve size was selected based on annular perimeter measurements that were obtained from multislice computed tomography (MSCT) prior to the TAVR procedure. Device oversizing was calculated as follows: [(perimeter of the prosthesis – MSCT derived perimeter of the annulus) / MSCT derived perimeter of the annulus) × 100].
All centers were asked to comply with the following recommendations: 1) balloon valvuloplasty using an undersized straight balloon; 2) temporary high-frequency pacing during balloon valvuloplasty; 3) a waiting period ≥3 days prior to PPI if clinically justified; 4) PPI based on Class I or II 2007 ESC guidelines as determined by 12-lead surface electrocardiogram (ECG); and 5) use of pacemakers with the managed ventricular pacing (MVP) feature (or similar) and the ability to provide rhythm analysis reports. MVP was intended to promote intrinsic conduction, thereby allowing the pacemaker to be programmed to minimize unnecessary ventricular pacing.
Implant depth was defined as the maximal distance (millimeters) between the intraventricular end of the bioprosthesis and the aortic annulus at the level of the noncoronary cusp, as measured by angiography in the projection chosen for deployment. Implant depth was measured during the procedure by the operator and off-line by an independent core laboratory (Cardialysis, Rotterdam, the Netherlands). “Correct implantation” was defined as a depth ≤6 mm below the annulus plane, and a depth >6 mm was considered to be a low implantation.
ECG data collection
Twelve-lead ECG recordings were obtained before and immediately after TAVR and at 7 and 30 days of follow-up. Traces were examined by a core laboratory (Cardialysis) for rate and rhythm using the criteria of the World Health Organization and International Society and Federation for Cardiology Task Force (9).
Echo data collection
Transthoracic echocardiography (TTE) was performed prior to TAVR and at days 7 and 30 post-TAVR. Images were examined by the core laboratory (Cardialysis). Paravalvular leak was determined according to VARC-1 (Valvular Academic Research Consortium-1) criteria (10).
Study design and endpoints
The ADVANCE II study was a prospective, multicenter, observational study performed in 9 high-volume European centers. The primary endpoint was the incidence of new-onset Class I or Class II indications for PPI (including sinus node disease, acquired atrioventricular (AV) block, and bifascicular/trifascicular block) according to ESC guidelines at 30 days post-procedure in patients with a MCS implanted at a depth of ≤6 mm below the aortic annulus. An independent advisory committee consisting of 3 electrophysiologists adjudicated the indication for all PPI.
Secondary endpoints included: 1) evaluation of safety outcomes according to VARC-2 (11) definitions adjudicated by an independent clinical events committee; 2) characterization of CD by 12-lead ECG before TAVR, post-procedure, and at 7 and 30 days post-TAVR; 3) exploration of the determinants of AV and interventricular (IV) conduction abnormalities; and 4) determining the frequency of pacing and pacemaker dependency in patients with a new PPI, assessed at 30 days using pacemaker interrogation.
The ethics committee at each center approved the study protocol, and written informed consent was obtained from all patients. The study was conducted in accordance with the Declaration of Helsinki. The study was designed and funded by Medtronic Inc.
Continuous variables are reported as mean ± SD, mean ± SE, and median and interquartile range, where appropriate. Categorical variables are reported as frequencies and percentages. PPI rates and other outcome rates were calculated using Kaplan-Meier analysis. For patients without an event, the date of censoring was the latest date of all follow-up visits (including study exit) and events (including death). Corresponding 2-sided 95% confidence intervals (CIs) were constructed using the Peto standard error. Thirty-day PPI Kaplan-Meier rates were compared between implant depth groups (≤6 mm vs. >6 mm) using a z test. Implant depth and percentage of oversizing comparisons were based on pooled Student t tests, and post-dilation percentages were compared using Fisher exact tests. McNemar test was used to compare paired data of new-onset left bundle branch block (LBBB) and first-degree AV block between baseline versus 7 days post-implantation, and 7-days versus 30-days post-implantation. Cox regression models were used to determine significant predictors of PPI. Univariable predictors of PPI with a p value <0.20 were entered in the multivariable model. Receiver operating curves were derived to assess the predictive value of implant depth on PPI. The trend of implant depth groups by valve size was tested using a Cochran-Armitage trend test. Changes in intrinsic rate percentages from 7 to 30 days were based on generalized estimating equations accounting for repeated measures for patients with paired data, and the changes in percentage of ventricular pacing were tested using a signed rank test to account for the non-normality of the values. All analyses were performed using SAS software (version 9.3, Cary, North Carolina).
Demographic and baseline characteristics
Between October 13, 2011 and April 16, 2013, 200 patients were enrolled, which represented approximately 65% of the total number of patients treated with the MCS in the participating centers. The demographic and clinical characteristics are described in Table 1. The mean age of the population was 80.2 ± 6.7 years and the mean Society of Thoracic Surgeons score was 7.2 ± 6.8. Most of the patients were in New York Heart Association class III or IV (74.4%).
AV conduction was normal in 75.8% of patients, whereas IV conduction was normal in 76.8%. TTE showed the mean aortic valve area to be 0.8 ± 0.2 cm2 and the mean gradient 42.4 ± 14.4 mm Hg, with a preserved left ventricular ejection fraction in 53.7% of the population. Imaging and ECG parameters are summarized in Table 2.
Of 200 patients enrolled, 6 did not receive a MCS bioprosthesis (1 patient refused implantation, 3 were reassigned to AVR, 1 received a new PPI after enrollment but before treatment, and 1 was treated with a different TAVR prosthesis). Between implantation and day 30, 5 patients had died, 1 patient withdrew consent, and 5 patients missed their 30-day follow-up visit. Therefore, 183 of the 194 implanted patients were available for 30-day follow-up.
Valve sizing was based on MSCT measurements in 89.7% of the patients and on TTE in the remaining 10.3%. The following MCS sizes were implanted: 23 mm in 2.6%, 26 mm in 29.9%, 29 mm in 55.2%, and 31 mm in 12.4% of patients. Transfemoral access was used in 89.7% of the procedures, whereas 6.2% and 4.1% of the procedures were from the subclavian and direct aortic approach, respectively. Aortic valve pre-dilation was performed in 96.4% of patients, using a straight balloon in 73.3%, whereas post-dilation was performed in 22.2%. Two valves were implanted in 7.7% of patients (valve-in-valve in 2.1% and embolization of the first valve into the aorta in 5.7%).
Core lab-assessed implant depth measurements were available in 192 of the treated patients. The mean depth of implantation in the overall population was 6.9 ± 4.3 mm. The target depth of ≤6 mm was reached in 83 patients (43.2%), and the mean implantation depth in this group was 3.0 ± 2.2 mm. The target was not reached in 109 patients (56.8%), and the mean implant depth was 9.9 ± 2.8 mm.
Primary endpoint and new conduction disturbances
The overall 30-day Kaplan-Meier rate of new PPI with Class I/II indications according to the guidelines was 18.2% (n = 35). An acquired AV block was the main indication for PPI (34 of 35; 97.1%). Twelve patients received a permanent pacemaker without a Class I/II indication as adjudicated by the independent advisory committee, bringing the total PPI rate to 24.4% (Table 3). Within the subgroup of patients with available implant depth (n = 192), the rate of PPI with class I/II indications was 17.8% (n = 34, 1 patient with a Class I/II indication was missing implant depth). The rate of PPI for Class I/II indications in patients with implantation of the MCS at a depth ≤6 mm was 13.3% (n = 11). In patients with low implantation >6 mm, the PPI rate with Class I/II indications was 21.4% (n = 23) (Figure 1).
Of the 35 patients with a Class I/II indication for PPI regardless of implant depth, 34 were implanted during the index hospital stay. Importantly, no episodes of third-degree AV block or sudden death occurred between discharge and 30 days post-TAVR.
The timing of new-onset CD is described in Table 4. The most frequent CD were new LBBB and first-degree AV block. According to a paired analysis in patients with normal conduction at baseline and an available ECG at post-procedure (within 48 h), day 7, and day 30 (n = 97 for LBBB, n = 59 for first-degree AV block), LBBB and first-degree AV block resolved by 30 days in 43.2% and 73.9%, respectively, as shown in Figure 2.
New Class I/II PPI at 30 days and all new CD were significantly associated with low MCS implantation (Figure 3). No relation was observed between new CD and oversizing, which was observed in 10.9% (n = 19) of patients with available MSCT data. Similarly, post-dilation was not related to any CD.
The only independent predictor of new PPI for Class I/II indications at 30 days by multivariable analysis was implantation depth (hazard ratio: 1.12 per 1 mm depth increase; 95% CI: 1.04 to 1.22; p = 0.005).
By receiver operating curve analysis, an implantation depth of <4 mm, which was achieved in 25.5% of the patients, was found to have the best negative predictive value (93.9%) for new PPI, although the positive predictive value was only 21.7% (sensitivity 91.2%, specificity 29.1%).
Finally, smaller MCS bioprosthesis size was associated with a higher rate of optimal implantation depth, which decreased from 80% to 51.7%, 41.0%, and 25.0% for the 23-, 26-, 29-, and 31-mm valve sizes, respectively (p = 0.008) (Figure 4).
Interrogation of pacemakers implanted for Class I/II indications regardless of implant depth showed that the rate of available intrinsic rhythm, evaluated via transient VVI programming at 30 beats/min, significantly increased from 25.9% at 7 days to 59.3% at 30 days (p = 0.004). We also observed a trend of reduced ventricular pacing time from 7 to 30 days (from 90.7 ± 24.1% to 80.8 ± 32.8%, p = 0.135). An MVP algorithm was available at the 7-day interrogation in 64.3% of patients and activated in 66.7% of them, whereas at 30-day follow-up, it was available in 56.3% of patients and activated in 50.0% of them. A trend toward a reduction in the activation of MVP was observed between 7- and 30-day follow-up, whereas no significant change was observed in other parameters.
Acute and 30-Day Outcomes
The 30-day Kaplan-Meier rates of adverse events were as follows: all-cause mortality and cardiovascular mortality 1.6%; stroke 2.1%; life-threatening or disabling bleeding 4.1%; major vascular complications 11.9%; myocardial infarction 0.5%; and acute kidney injury (stage III) 0.5%. Paravalvular leak was moderate or severe in 8.5% of patients and mild or less in 91.5%. These data are summarized in Table 3.
This is the first observational TAVR study with prospectively applied best implantation practices, rigorous data collection, and independent core laboratory analysis of all imaging and electrocardiographic data. Moreover, the acute and 30-day results showed a very low rate of major adverse cardiac and cerebrovascular events, in agreement with the most recent randomized TAVR trial with the MCS (1).
The close anatomic relationship between the aortic valve and some of the components of the cardiac conduction system explains the frequent occurrence of CD after interventions on the aortic valve. The MCS bioprosthesis contains of a self-expanding Nitinol frame with a high radial force that interacts with tissue a few millimeters below the aortic annulus, where the left bundle branch emerges from the left side of the ventricular septum (12). Mechanical compression leading to temporary inflammation or permanent damage in the conduction pathways is probably the main determinant of CD. This mechanism may be affected further by anatomic characteristics such as the presence of extensive calcium deposits (3) or by procedural steps such as crossing of the aortic valve with a wire and valvuloplasty (13).
Factors associated with permanent pacemaker implantation rate
In addition to the pre-operative electrocardiographic and anatomic features that can influence the occurrence of CD, it is important to consider the impact of implantation technique. Among several studies focused on the search for the predictors of PPI, most identified implantation depth as an independent predictor (14–17), whereas a few did not confirm this association (5,18). However, these studies were mostly retrospective, were not homogeneous in procedural technique, and included small cohorts of patients. The importance of the correct implantation depth of the MCS was originally highlighted by Piazza et al. (12), and recently Tchetche et al. (6) demonstrated that a high implantation using the AccuTrak delivery system allowed for a reduction in new PPI. The importance of implantation depth to prevent LBBB was also described for the balloon-expandable prosthesis by Urena (19). The ADVANCE II study is a prospective observational study designed to examine the best possible results by ensuring homogenous patient selection and procedural technique. Although the mean implantation depth in the overall population was close to 6 mm (6.9 ± 4.3 mm), in those patients in whom a correct implantation was achieved, the mean depth was 3.0 ± 2.2 mm. This is comparable to that obtained in the experience described by Tchetche et al. (6). The importance of a shallow implantation depth in limiting the need for PPI after TAVR was confirmed by the 4-mm cutoff value obtained in our study. In particular, a depth shallower than 4 mm was associated with a Kaplan-Meier rate of Class I/II PPI of 6.1%.
The importance of implantation depth is also highlighted by the tight association with CD at 30 days (Figure 3), both for AV and IV disturbances. No significant association was observed between CD and either oversizing or post-dilation. This is at variance with Schroeter et al. (20), who described a relationship between CD onset and both oversizing and use of larger diameter prostheses. In our experience, oversizing was calculated based on the nominal perimeter of the MCS and not on a direct measure after implantation and was observed in only 10.9% of patients. Importantly, prosthesis size was decided according to pre-operative MSCT measurements in 89.7% of patients and not on TTE measurements as in previous studies (21). In addition, in the ADVANCE II study, all 4 valve sizes were used, in contrast to the majority of previous studies in which the 23-mm and 31-mm prostheses were seldom used. Interestingly, as valve size increased, the probability of a low implant depth increased (p = 0.008), possibly related to the wider frame design. This last observation could in part explain the fact that optimal MCS implantation was reached in only one-half of the population. The depth of implantation with larger valves can be partially controlled by careful manipulation of the stiff wire in combination with controlled pacing (100 to 120 beats/min) during the first third of deployment; however, these maneuvers do not guarantee exact positioning. The attempt to obtain optimal implantation may explain the incidence of valve-in-valve (2.1%) and embolization (5.7%) (Table 3).
In our experience post-dilation was not associated with the occurrence of new CD; however, the limited number of patients undergoing post-dilation in the study (possibly because of the frequent use of pre-dilation) does not allow generalization of this finding.
Some of the baseline ECG parameters that were previously described to predict new CD after TAVR, including right bundle branch block, left anterior hemiblock, and atrial fibrillation were not associated with PPI on multivariable analysis. This may be a result of patient selection bias, as normal baseline ECG was preferred to facilitate the interpretation of new-onset CD.
Indications for new permanent pacemakers
In the design of the ADVANCE II study, adherence to the 2007 ESC guidelines on pacing was recommended, which is in contrast to previous studies that either did not specify the indications (17) or used prophylactic pacing in patients with new LBBB and prolonged PR interval (3,22). In our study, all new PPI but 1 were implanted during the index hospital stay, and no adverse events related to CD were observed at 30 days. In addition, no total AV block or sudden death occurred between discharge and 30 days. A reason for very early or prophylactic PPI may be the push for early discharge for economic reasons, favored by the decrease in procedural complications in recent years. However, the expansion of TAVR to lower risk and younger patients in the future will require a careful approach to PPI. Thygesen et al. (23) recently demonstrated in a retrospective analysis a reduction in PPI from 27.4% to 19.7% simply by reassessing indications to PPI. Accordingly, our rigorous pacing policy resulted in a PPI rate of 18.2%, which is similar to the rate reported in the most recent randomized TAVR trial (1) and reached 13.3% in patients with correct implantation. Absence of rigorous criteria explain the different incidence of new PPI in the CHOICE (A Comparison of Transcatheter Heart Valves in High Risk Patients With Severe Aortic Stenosis) trial (24) that may have led to a high rate not only for MCS prosthesis (37.6%) but also for Sapien XT device, where it reached 17.3%.
Timing and resolution of conduction disturbances
A high rate of new AV and IV CD was observed within the first 48 h of TAVR, with a significant resolution by 30 days (Table 4). Specifically, the rate of new LBBB and first-degree AV block had decreased by 43.2% and 73.9%, respectively (Figure 2), in agreement with previous observations (14,19,25) and similar to the recent data from the PARTNER (The PARTNER trial: Placement of Aortic Transcatheter Valve Trial) (26) on LBBB where 57.9% of the new-onset LBBB resolved at 30 days after balloon-expandable valve implantation. The transient nature of these CD can be explained in part by the temporary inflammation caused by the mechanical trauma occurring during the various steps of the TAVR procedure (13). This finding supports the importance of avoiding a liberal use of early PPI after TAVR. In particular, the occurrence of a new LBBB in a patient with a normal baseline ECG should not be an indication for pacing. Investigation of the sub-Hisian conduction with an electrophysiologic study in patients with new LBBB and very long PR interval (>300 ms), especially when these CD persist for over 72 h, may be advocated.
Finally, we observed a significant increase in the rate of available intrinsic rhythm at 30 days, together with a trend of reduced ventricular pacing time. Therefore, even with a conservative pacing policy as in our study, some implants prove unnecessary in the short term, in agreement with recent findings (23).
This study describes conduction disturbances and new PPI after MCS implantation with pre-defined indications in a relatively small population. The low baseline prevalence of atrial fibrillation (10.5%) and pre-operative AV (24.2%) and IV (23.2%) CD should be considered a potential selection bias that could have reduced the incidence of PPI and prevented generalization of the results. Patients with persistent and permanent atrial fibrillation were excluded to reduce ambiguous or unfeasible interpretation of CD following TAVR. The lack of ambulatory ECG monitoring in the follow-up analysis should be taken in account in the evaluation of CD resolution at 7 and 30 days.
Although the study included 9 sites very experienced in MCS implantation, optimal implant depth was only achieved in 43.2% of the patients. At the moment, the new PPI rate of 13.3% may be the best result achievable with the present device and delivery system.
CD are multifactorial events occurring after both surgical valve replacement and TAVR that should be monitored and properly treated. The tendency toward CD resolution after TAVR and the rarity of late-onset complete AV block support a conservative approach to PPI that is driven by international guidelines. For this reason, it appears mandatory to avoid the practice of unnecessary or prophylactic pacemaker implantation. The best results can be obtained with a careful, high implantation of the MCS prosthesis; however, in this study, the optimal implant depth was achieved in less than 50% of patients. It is likely that newer generation devices that are repositionable and recapturable will improve the ability to properly position the device. This may lead to reduced rates of PPI, which is of key importance as the use of TAVR in lower-risk and younger patients is under consideration.
WHAT IS KNOWN? The rates of new PPI and their indications in TAVR, especially with self-expanding devices, vary widely.
WHAT IS NEW? In this study, optimal deployment with high implant depth as well as strict adherence to international guidelines on the management of conduction disturbances resulted in a lower rate of PPI. In this set-up, there is a negligible risk of adverse events after hospital discharge.
WHAT IS NEXT? New device designs, including repositionable systems, will allow for better control of device positioning within the landing zone and might further improve the rate of PPI.
The authors thank Francesca Barbieri, MD, Rijk de Jong, MSc, and Maarten Hollander, MSc, from Medtronic Bakken Research Center (Maastricht, the Netherlands) for overall study management. They further acknowledge all investigators for their promptness and skill during enrollment and follow-up.
Medtronic Inc. funded the ADVANCE II study. Drs. Petronio, Kovac, and de Jaegere are clinical proctors and consultants for Medtronic, Inc. Dr. Sinning has received research grants from Medtronic and Edwards Lifesciences; and speaker honoraria from Medtronic, Edwards Lifesciences, Abbott, and Direct Flow Medical. Dr. Van Mieghem has received research grants from Claret Medical, Edwards Lifesciences, Boston Scientific, and Medtronic, Inc. Dr. Zucchelli is a consultant for Medtronic, Inc. Dr. Nickenig has received a research grant and consulting and speaker honoraria from Medtronic, Inc. Drs. Bosmans, Bedogni, and Branny are proctors for Medtronic, Inc. Ms. Schiltgen is an employee of Medtronic, Inc. Ms. Kraus is a contractor of Medtronic, Inc. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- Abbreviations and Acronyms
- conduction disturbances
- confidence interval
- European Society of Cardiology
- left bundle branch block
- Medtronic CoreValve System
- multislice computed tomography
- managed ventricular pacing
- permanent pacemaker implantation
- transcatheter aortic valve replacement
- transthoracic echocardiography
- Received February 6, 2015.
- Accepted February 12, 2015.
- 2015 American College of Cardiology Foundation
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