Micra AV leadless pacemaker implantation after transcatheter aortic valve implantation.

BACKGROUND: Transvenous pacemaker (PM) implantation is a complication in patients undergoing transcatheter aortic valve implantation (TAVI). Recently, a second generation of leadless PMs able of atrioventricular (AV) synchronous pacing has been introduced and could be an alternative when ventricular pacing is required after TAVI. Real-world data on Micra AV after TAVI are still lacking. Our aim was to determine the per- and post-procedural outcomes in patients with Micra AV leadless PM implantation after TAVI. METHODS: A total of 20 consecutive patients underwent Micra AV leadless PM implantation after TAVI between November 2020 and June 2021. RESULTS: The main indication for ventricular pacing was high-degree AV block (55% of patients) and left bundle branch block (LBBB) associated with prolonged HV interval (45% of patients). At discharge, mean (SD) ventricular pacing threshold was 0.397 ± 0.11 V at 0.24 ms and ventricular impedance was 709.4 ± 139.1 Ω. At 1-month follow-up, 95% of patients were programmed in VDD pacing mode. Mean (SD) ventricular pacing threshold was 0.448 ± 0.094 V at 0.24 ms. In patients with ventricular> pacing > 90% (n = 5), mean AM-VP was 72.5% ± 8.3%. Pacing threshold at 1 month was not significantly different compared to discharge (p = .1088). Mean (SD) impedance was 631.0 ± 111.9 Ω, which remained stable at discharge (p = .0813). No procedural complications occurred during implantation. At 1-month follow-up, two patients displayed atrial under-sensing. CONCLUSIONS: Micra AV leadless PM implantation after TAVI is associated with a low complication rate and good device performance at 1-month post-implantation.

An improved window of interest for electroanatomical mapping of atrial tachycardia.

PURPOSE: Diagnosis of atrial tachycardia (AT) with 3D mapping system remains challenging due to fibrosis or previous ablation. This study aims to evaluate a new electroanatomical mapping annotation setting using a window of interest adjusted at the end of the P wave (WOIp wave) to identify the AT mechanism more accurately. METHODS: Twenty patients with successful ablation of left AT using navigation system CARTO3 were evaluated. Two maps for each patient were generated offline using either conventional settings of WOI (WOIconv.) or WOIp wave. Three investigators from two centres analysed the maps blindly. RESULTS: Mechanisms of AT were macroreentrant in 14/20 patients (70%) and focal in 6/20 (30%). WOIp wave resulted in a significant increase in the percentage of correct identification of the mechanism based on mapping alone (93.3 ± 13.7% vs 58.3 ± 33.9%; p = 0.0003) compared with WOIconv.. Diagnoses based on mapping were arrived at faster (27.8 ± 16.4 s vs 38.97 ± 13.64 s, respectively; p = 0.0231) and with a greater confidence in the diagnosis (confidence index 2.57 ± 0.45 vs 2.12 ± 0.45, respectively; p = 0.0024). With perimitral re-entry specifically "early meets late" was closer to the anatomical region of the mitral isthmus (15.9 ± 20.9 mm vs 48.77 ± 23.23 mm, respectively; p = 0.0028). CONCLUSIONS: This study found that electroanatomical mapping acquisition with a window of interest set at the end of the P wave improves the ability to diagnose the arrhythmia mechanism based on the initial map. It is particularly beneficial in identifying area of interest for ablation in perimitral AT.