key: cord-0854809-hlc9nred
authors: Erinne, Ikenna; Theertham, Arjun K.; Maleki, Kataneh; Chen, Chunguang; Russo, Mark; Hakeem, Abdul
title: Complete Atrioventricular Block: A Rare Complication of MitraClip Implantation
date: 2021-05-19
journal: JACC Case Rep
DOI: 10.1016/j.jaccas.2021.02.044
sha: ce2d2402e1f33441222d0ffe4786360b7ce34546
doc_id: 854809
cord_uid: hlc9nred

MitraClip (Abbott Vascular, Inc., Santa Clara, California) has emerged as a viable alternative for treatment of symptomatic severe mitral regurgitation. Conduction abnormalities are not a known complication of this procedure. We report a case of complete heart block without a ventricular escape rhythm immediately following MitraClip placement near the medial leaflets (A3-P3) in a patient with underlying trifascicular block. (Level of Difficulty: Intermediate.)

In patients undergoing transcatheter MV repair, underlying conduction abnormalities can increase the risk of complete heart block and generate the need for a permanent pacemaker. The close proximity of the conduction system relative to the MV apparatus explains the risk of heart block from instrumentation of the MV apparatus. Pre-procedural and intraoperative electrocardiographic monitoring help identify patients at risk for this complication. however, the reason for the pacemaker was not provided. Notably, pacemaker implantation was not reported in several other studies assessing MC complications. (3, 5) . Similarly, complete AV block is uncommon following surgical MV repair. A previous study of 115 consecutive patients who underwent surgical MV repair found that 7 (6%) patients developed complete AV block in the immediate postoperative period; 4 of these cases were transient, and the patients recovered before discharge, and 3 were permanent and required permanent pacing (6) . There were no independent predictors found for the incidence of AV block following surgery, but AV node stunning during cardioplegic arrest and damage to the AV node artery because it courses near the posterolateral part of the MV annulus were identified as potential causes (6,7) We report a rare case of AV block complicating (8) . Although this case was procedurally different from MC implantation, the mechanism of conduction damage in the current case is likely similar given our patient's small LV cavity and the proximity of instrumentation to the posteromedial commissure, which lies close to the AV conduction system ( Figures 4A and 4B, Supplemental Figure 1 ).

The patient was discharged on post-operative day 1, and there was no evidence of AV conduction recovery on day 7 clinic follow-up. The persistence of a conduction defect suggests true structural damage to the left posterior fascicle (in the presence of pre-existing right bundle branch block and left anterior fascicular block) related to the procedure rather than a reversible cause, as would be expected from a complication related to general anesthesia.

As the use of transcatheter MV therapy becomes more widespread, it is important to anticipate the potential for complications related to the conduction system, especially in patients with underlying conduction disease, as has been the cautious approach for transcatheter aortic valve implantation. Identification of such patients will allow for better preparation for emergency temporary pacing intraoperatively and monitoring in an intensive cardiac unit for a longer time. At our institution, prolonged electrocardiographic monitoring with an ambulatory event monitor is routinely implemented following transcatheter aortic valve implantation. In these high-risk patients undergoing MC implantation who do not have conduction abnormalities intraoperatively, a similar approach may be of clinical utility. However, additional data on long-term outcomes are needed to confirm these suggestions.

The authors have reported that they have no relationships relevant to the contents of this paper to disclose. 

The EVEREST II trial: design and rationale for a randomized study of the evalve MitraClip system compared with mitral valve surgery for mitral regurgitation

Transcatheter mitral-valve repair in patients with heart failure

One-year outcomes after MitraClip for functional mitral regurgitation

Risk and outcomes of complications during and after MitraClip implantation: experience in 828 patients from the German TRAnscatheter Mitral valve Interventions (TRAMI) registry

Complications following percutaneous mitral valve repair

Frequency, predictors, and consequences of atrioventricular block after mitral valve repair

Incidence and pathophysiology of atrioventricular block following mitral valve replacement and ring annuloplasty

Unexpected delayed complete atrioventricular block after Cardioband implantation

Transcatheter mitral valve regurgitation treatment: state of the art and a glimpse to the future

KEY WORDS cardiac pacemaker, complication, mitral valve APPENDIX For supplemental videos and a figure, please see the online version of this paper.