Occurrence and Persistency of Conduction Disturbances during Transcatheter Aortic Valve Implantation

Background and Objectives: Conduction disturbances such as left bundle branch block (LBBB) and complete atrio-ventricular block (cAVB) are relatively frequent complications following trans-catheter aortic valve implantation (TAVI). We investigated the dynamics of these conduction blocks to further understand luxating factors and predictors for their persistency. Materials and Methods: We prospectively included 157 consecutive patients who underwent a TAVI procedure. Electrocardiograms (ECGs) were obtained at specific time points during the TAVI procedure and at follow-up until at least six months post-procedure. Results: Of the 106 patients with a narrow QRS complex (nQRS) before TAVI, ~70% developed LBBB; 28 (26.4%) being classified as super-transient (ST-LBBB), 20 (18.9%) as transient (T-LBBB) and 24 (22.6%) as persistent (P-LBBB). Risk of LBBB was higher for self-expandable (SE) than for balloon-expandable (BE) prostheses and increased with larger implant depth. During the TAVI procedure conduction disturbances showed a dynamic behavior, as illustrated by alternating kinds of blocks in 18 cases. Most LBBBs developed during balloon aortic valvuloplasty (BAV) and at positioning and deployment of the TAVI prosthesis. The incidence of LBBB was not significantly different between patients who did and did not undergo BAV prior to TAVI implantation (65.3% and 74.2%, respectively (p = 0.494)). Progression to cAVB was most frequent for patients with preexisting conduction abnormalities (5/34) patients) and in patients showing ST-LBBB (6/28). Conclusions: During the TAVI procedure, conduction disturbances showed a dynamic behavior with alternating types of block in 18 cases. After a dynamic period of often alternating types of block, most BBBs are reversible while one third persist. Patients with ST-LBBB are most prone to progressing into cAVB. The observation that the incidence of developing LBBB after TAVI is similar with and without BAV suggests that a subgroup of patients has a substrate to develop LBBB regardless of the procedure

Dynamic atrioventricular delay programming improves ventricular electrical synchronization as evaluated by 3D vectorcardiography

Background: Optimal timing of the atrioventricular delay in cardiac resynchronization therapy (CRT) can improve synchrony in patients suffering from heart failure. The purpose of this study was to evaluate the impact of SyncAV (TM) on electrical synchrony as measured by vectorcardiography (VCG) derived QRS metrics during biventricular (BiV) pacing. Methods: Patients implanted with a cardiac resynchronization therapy (CRT) device and quadripolar left ventricular (LV) lead underwent 12-lead ECG recordings. VCG metrics, including QRS duration (QRSd) and area, were derived from the ECG by a blinded observer during: intrinsic conduction, BiV with nominal atrioventricular delays (BiV Nominal), and BiV with SyncAV programmed to the optimal offset achieving maximal synchronization (BiV + SyncAV Opt). Results: One hundred patients (71% male, 40% ischemic, 65% LBBB, 32 +/- 9% ejection fraction) completed VCG assessment. QRSd during intrinsic conduction (166 +/- 25 ms) was narrowed successively by BiV Nominal (137 +/- 23 ms, p <.05 vs. intrinsic) and BiV + SyncAV Opt (122 +/- 22 ms, p Conclusion: With VCG-based, patient-specific optimization of the programmable offset, SyncAV reduced electrical dyssynchrony beyond conventional CRT. Crown Copyright (C) 2019 Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)