Kara M. Stout, DO, MPH; Harsh Golwala, MD; Faisal Latif, MD, FSCAI; and Andrew M. Goldsweig, MD, MS, FSVM, RPVI, FSCAI

Introduction

Transcatheter aortic valve replacement (TAVR) has become the most prevalent treatment strategy for severe aortic stenosis. Despite improvements in the procedural process, there remains a significant risk of causing new onset left bundle branch block (LBBB) or high-degree atrioventricular block (HAVB)/complete heart block (CHB) requiring permanent pacemaker (PPM) implantation.^{1, 2} In this Tip of the Month, we focus on the management of these conduction disturbances post-TAVR. Our review follows the framework of the 2019 Journal of the American College of Cardiology (JACC) Scientific Expert Panel Statement, comprised of a pre-procedural risk assessment, procedural considerations, and post-procedural evaluation.³ Another recent expert consensus decision pathway from the American College of Cardiology (ACC) Solution Set Oversight Committee affirms this pathway and discusses the pre-procedural and intraprocedural considerations in detail.⁴

Pre-Procedural Assessment

Eliciting a history of symptoms related to a bradyarrhythmia may be helpful in determining which patients are at higher risk for conduction disturbances.⁴ The presence of a pre-procedural right bundle branch block (RBBB) is associated with an increased risk of PPM implantation at 30 days (40.1 percent vs. 13.5 percent; p < 0.001) as well as cardiovascular (hazard ratio [HR]: 1.45; 95 percent; confidence interval [CI]: 1.11 to 1.89; p = 0.006) and all-cause mortality (HR: 1.31; 95 percent CI: 1.06 to 1.63; p = 0.014) at 20 months post-TAVR.⁵ While limited data exists for other conduction abnormalities, a baseline first-degree atrioventricular block (AVB) in patients undergoing a SAPIEN-3 valve (Edwards Lifesciences, Irvine, CA) was also associated with a higher incidence of 30-day PPM implantation (odds ratio 4.005; 95 percent CI 2.386–6.723; p < 0.001).⁶

• Patients with unstable conduction conditions may benefit from continuous electrocardiogram (EKG) monitoring for 24 hours preoperatively.

Procedural Considerations

• Continuous EKG monitoring should be performed intraoperatively.
• A temporary transvenous pacemaker (TVP) should be placed at the beginning of the procedure.
• When balloon valvuloplasty pre-dilation was more common, half of conduction disturbances occurred during pre-dilation before transcatheter heart valve (THV) implantation, partly due to transient injury to the conduction system with the balloon inflation in the left ventricular outflow track [7].⁷
• TAVR device-specific conduction disturbance data are limited due to a lack of head-to-head trials. A self-expanding prosthesis is associated with higher risk of PPM implantation compared with a balloon-expandable prosthesis;⁸ however, this gap is closing due to tailored implantation techniques.
• Implantation depth >5–7 mm below the aortic annulus has been associated with an increased risk of new LBBB.³

Post-Procedural Considerations

An immediate post-procedure EKG is recommended to risk stratification patients for lasting conduction disturbances (see Figure 1):

Group 1: No EKG changes in patients without pre-existing RBBB:

• These patients are low risk for conduction disturbances, and the TVP can be discontinued post-operatively.
• An EKG on post-operative day 1 (POD #1) after telemetry for 24 hours is recommended, with early hospital discharge on POD #1 if there are no arrhythmias.

Group 2: No EKG changes in patients with pre-existing RBBB:

• The TVP should be maintained for 24 hours with daily EKG/telemetry monitoring for two days, with discharge on POD #2 if no arrhythmias arise.
• Prophylactic PPM in patients with a previous RBBB is not recommended.
• For patients with a persistent increase in the PR or QRS duration ³20 ms who are at a high risk of HAVB/CHB, an invasive electrophysiology study (EPS) or continuous EKG monitoring for 48 hours to four weeks to guide PPM decision-making or empiric PPM placement. An EPS demonstrating an Infra-Hisian block during atrial pacing or HV interval >100 ms indicates the need for PPM placement. Rapid atrial pacing after TAVR with the absence of a developed Wenckebach AVB may also be a helpful negative predictor for PPM implantation (13.1 percent vs. 1.3 percent; p < 0.001).⁸

Group 3: EKG changes with a persistent increase in the PR or QRS duration ³20 ms in patients with a pre-existing RBBB, LBBB, intraventricular conduction delay (IVCD) with QRS ³120 ms, or first-degree AVB:

• Maintain TVP for 24 h with serial EKG/telemetry monitoring for 2 days, with discharge on POD #2 if EKG changes regress or are stable with a QRS ≤150 ms and PR ≤240 ms.
• At 24 hours post-TAVR, if the QRS remains >150ms, the PR remains >240 ms, the QRS or PR are >20 ms than the baseline, or there are further EKG changes with ≥20 ms increase in PR or QRS, the TVP should be maintained for another 24 hours. If there is no regression of these changes, the patient is considered high risk for HAVB/CHB. As discussed with group 2, an EPS, continuous EKG monitoring, or empiric PPM placement can be considered.
• An isolated increase in PR >240 ms without other EKG changes should not prompt PPM placement.

Group 4: New-onset LBBB:

• A new LBBB is the most common conduction disturbance after TAVR, occurring in about 25 percent of cases.² It is frequently associated with deployment of the first-generation CoreValve system at 6–8 mm below the aortic annulus, with little data from the newer generations of THV.²
• Perioperative LBBB resolves at least partially in 50 percent of cases, and patients with a LBBB that is stable after 48 hours are safe to discharge without PPM placement.²
• If there is further prolongation of the PR/QRS, the TVP should be maintained until POD #2; if these changes persist, the patient is considered high risk for HAVB/CHB. An EPS, continuous EKG monitoring, or empiric PPM placement can be considered.

Group 5: New-onset HAVB or CHB:

• More than 80 percent of the associated HAVB or CHB occur during the TAVR procedure; if either are seen intraoperatively or post-operatively, PPM placement is indicated. There is little likelihood that these conduction disturbances will improve over time, so there is no benefit to prolonged monitoring before PPM.

Conclusion

Post-TAVR conduction disturbances are common and, therefore, a major focus of innovation both for THV and procedural design. Further data are needed to provide higher-level evidence-based guidelines to unify treatment strategies.

References

1. Auffret V, Lefevre T, Van Belle E, et al. Temporal Trends in Transcatheter Aortic Valve Replacement in France: FRANCE 2 to FRANCE TAVI. J Am Coll Cardiol. 2017 Jul 4;70(1):42–55.
2. Auffret V, Puri R, Urena M, et al. Conduction Disturbances After Transcatheter Aortic Valve Replacement: Current Status and Future Perspectives. Circulation. 2017 Sep 12;136(11):1049–69.
3. Rodés-Cabau J, Ellenbogen KA, Krahn AD, et al. Management of Conduction Disturbances Associated With Transcatheter Aortic Valve Replacement: JACC Scientific Expert Panel. J Am Coll Cardiol. 2019 Aug 27;74(8):1086–1106.
4. Lilly SM, Deshmukh AJ, Epstein AE, Ricciardi MJ, Shreenivas S, Velagapudi P et al. 2020 ACC Expert Consensus Decision Pathway on Management of Conduction Disturbances in Patients Undergoing Transcatheter Aortic Valve Replacement: A Report of the American College of Cardiology Solution Set Oversight Committee. J Am Coll Cardiol. 2020 Nov 17;76(20):2391–2411.
5. Auffret V, Webb JG, Eltchaninoff H, et al. Clinical Impact of Baseline Right Bundle Branch Block in Patients Undergoing Transcatheter Aortic Valve Replacement. JACC Cardiovasc Interv. 2017 Aug 14;10(15):1564–1574.
6. Sammour Y, Sato K, Kumar A, et al. Impact of baseline conduction abnormalities on outcomes after transcatheter aortic valve replacement with SAPIEN-3. Catheter Cardiovasc Interv. 2021 Jul 1;98(1):E127–E38.
7. Nuis RJ, Van Mieghem NM, Schultz CJ, et al. Timing and potential mechanisms of new conduction abnormalities during the implantation of the Medtronic CoreValve System in patients with aortic stenosis. Eur Heart J. 2011 Aug;32(16):2067–74.
8. Krishnaswamy A, Sammour Y, Mangieri A, et al. The Utility of Rapid Atrial Pacing Immediately Post-TAVR to Predict the Need for Pacemaker Implantation. JACC Cardiovasc Interv. 2020 May 11;13(9):1046–1054.

Figure Legend

Figure 1. Algorithm for the proposed management of patients with conduction abnormalities after TAVR. Based upon a Journal of the American College of Cardiology (JACC) Scientific Expert Panel.³ TAVR = transcatheter aortic valve replacement, EKG = electrocardiogram, RBBB = right bundle branch block, LBBB = left bundle branch block, IVCD = intraventricular conduction delay, AVB = atrioventricular block, HAVB = high-degree atrioventricular block, CHB = complete heart block, TVP = transvenous pacemaker, POD = post-operative day, PPM = permanent pacemaker.