Groot, Natasja M.S. de

Abstract Objectives This study aimed to investigate the procedural characteristics, efficacy, and safety of atrioventricular junction (AVJ) ablation for atrial tachyarrythmia (AT) in patients with congenital heart disease (CHD). Background Although AVJ ablation is an established treatment option for intractable AT in the general population, there is no existing data on this treatment in patients with CHD. Methods Data were analyzed from an observational, retrospective, multicenter cohort, initiated jointly by the Pediatric and Congenital Electrophysiology Society and the International Society of Adult Congenital Heart Disease. Eleven centers contributed baseline, procedural and longitudinal data, including vital status, echocardiographic data, QRS duration, and NYHA class. Outcomes were assessed at early (3 months-1 year), and late follow-up (≥2 years) after AVJ ablation. Results A total of 66 patients (46.7 ± 20.2 years) underwent 71 AVJ ablations. In total, 58.5% had moderate or complex CHD, including 17.1% patients with a systemic RV or single ventricular circulation. The cumulative AVJ ablation success rate was 98.5%. An abnormal location of the atrioventricular conduction pathway was successfully targeted in 20.0% of the patients, which was significantly more common in patients with complex CHD compared to moderate or mild CHD (44.4%, 15.8%, and 3.6%, respectively; both P<0.05). Thirty-six patients (54.5%) underwent primary pacemaker implantation as part of the ‘pace and ablate’ strategy; final pacing modes were VVI pacing in 60.9%, and CRT/CSP in 39.1%. The transplant-free survival rates at 2, 5 and 10 years after AVJ ablation were 91.5%, 84.3%, and 69.0%, respectively. The acute and long-term complication rates were 3.0% and 13.6%, respectively. Conclusions AVJ ablation can be successfully performed in CHD patients with a high acute success rate and low complication rate. Anatomical challenges were common, which underscores the need for careful planning and operator experience. Given the acceptable long-term survival, these findings support the consideration of a ‘pace and ablate’ strategy in CHD patients with intractable AT.

Background The objective of this international multicenter study was to investigate both early and late outcomes of cardiac resynchronization therapy (CRT) in patients with a systemic right ventricle (SRV) and to identify predictors for congestive heart failure readmissions and mortality. Methods and Results This retrospective international multicenter study included 13 centers. The study population comprised 80 adult patients with SRV (48.9% women) with a mean age of 45±14 (range, 18–77) years at initiation of CRT. Median follow‐up time was 4.1 (25th–75th percentile, 1.3–8.3) years. Underlying congenital heart disease consisted of congenitally corrected transposition of the great arteries and dextro‐transposition of the great arteries in 63 (78.8%) and 17 (21.3%) patients, respectively. CRT resulted in significant improvement in functional class (before CRT: III, 25th–75th percentile, II–III; after CRT: II, 25th–75th percentile, II–III; P =0.005) and QRS duration (before CRT: 176±27; after CRT: 150±24 milliseconds; P =0.003) in patients with pre‐CRT ventricular pacing who underwent an upgrade to a CRT device (n=49). These improvements persisted during long‐term follow‐up with a marginal but significant increase in SRV function (before CRT; 30%, 25th–75th percentile, 25–35; after CRT: 31%, 25th–75th percentile, 21–38; P =0.049). In contrast, no beneficial change in the above‐mentioned variables was observed in patients who underwent de novo CRT (n=31). A quarter of all patients were readmitted for heart failure during follow‐up, and mortality at latest follow‐up was 21.3%. Conclusions This international experience with CRT in patients with an SRV demonstrated that CRT in selected patients with SRV dysfunction and pacing‐induced dyssynchrony yielded consistent improvement in QRS duration and New York Heart Association functional status, with a marginal increase in SRV function.

Abstract We aim to provide a critical appraisal of basic concepts underlying signal recording and processing technologies applied for (i) atrial fibrillation (AF) mapping to unravel AF mechanisms and/or identifying target sites for AF therapy and (ii) AF detection, to optimize usage of technologies, stimulate research aimed at closing knowledge gaps, and developing ideal AF recording and processing technologies. Recording and processing techniques for assessment of electrical activity during AF essential for diagnosis and guiding ablative therapy including body surface electrocardiograms (ECG) and endo- or epicardial electrograms (EGM) are evaluated. Discussion of (i) differences in uni-, bi-, and multi-polar (omnipolar/Laplacian) recording modes, (ii) impact of recording technologies on EGM morphology, (iii) global or local mapping using various types of EGM involving signal processing techniques including isochronal-, voltage- fractionation-, dipole density-, and rotor mapping, enabling derivation of parameters like atrial rate, entropy, conduction velocity/direction, (iv) value of epicardial and optical mapping, (v) AF detection by cardiac implantable electronic devices containing various detection algorithms applicable to stored EGMs, (vi) contribution of machine learning (ML) to further improvement of signals processing technologies. Recording and processing of EGM (or ECG) are the cornerstones of (body surface) mapping of AF. Currently available AF recording and processing technologies are mainly restricted to specific applications or have technological limitations. Improvements in AF mapping by obtaining highest fidelity source signals (e.g. catheter–electrode combinations) for signal processing (e.g. filtering, digitization, and noise elimination) is of utmost importance. Novel acquisition instruments (multi-polar catheters combined with improved physical modelling and ML techniques) will enable enhanced and automated interpretation of EGM recordings in the near future.