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In some patients with persistent atrial fibrillation (AF), localized functional mechanisms may sustain AF and thus represent ablation targets. We propose a novel mapping strategy to locate AF sources by combining repetitive patterns from consecutive high-density mapping recordings. The algorithm moves the catheter iteratively upstream of the main repetitive conduction direction to identify an AF source either by direct classification of local activation patterns or by encircling it. We tested the performance and robustness of this approach in two groups of detailed AF simulations, without and with severe structural remodeling (N=20 per group, 20 starting positions per simulation), using a 4times 4 grid mapping catheter (3mm spacing). Structural remodeling led to more simultaneous sources (median [IQR], 2 [1; 3] vs 3 [2; 5], p < 0.001) that meandered in larger areas (127.5 [82.0; 216.0] vs 188.0 [121.2; 305.5] mm2, p < 0.05. The mapping approach localized a source in 6 [4; 9] vs. 5 [5; 8] steps for the groups without and with structural remodeling (p < 0.001), with an accuracy of 11 [7; 16] vs 9 [6; 14] mm (p=0.046). Sources were localized by encircling in 62.6% vs. 41.4% of the detection in both groups, respectively. The proposed mapping strategy detected AF sources accurately within a few steps, even in complex AF substrates, with a substantial contribution of encircling to detect sources.

Cardiac resynchronization therapy (CRT) was proposed in the 1990s as a new therapy for patients with heart failure and wide QRS with depressed left ventricular ejection fraction despite optimal medical treatment. This review is aimed first to describe the rationale and the physiologic effects of CRT. The journey of the landmark randomized trials leading to the adoption of CRT in the guidelines since 2005 is also reported showing the high level of evidence for CRT. Different alternative pacing modalities of CRT to conventional left ventricular pacing through the coronary sinus have been proposed to increase the response rate to CRT such as multisite pacing and endocardial pacing. A new emerging alternative technique to conventional biventricular pacing, conduction system pacing (CSP), is a promising therapy. The different modalities of CSP are described (Hirs pacing and left bundle branch area pacing). This new technique has to be evaluated in clinical randomized trials before implementation in the guidelines with a high level of evidence.

AIMS: Pacing remote from the latest electrically activated site (LEAS) in the left ventricle (LV) may diminish response to cardiac resynchronization therapy (CRT). We tested whether proximity of LV pacing site (LVPS) to LEAS, determined by non-invasive three-dimensional electrical activation mapping [electrocardiographic Imaging (ECGI)], increased likelihood of CRT response. METHODS AND RESULTS: Consecutive CRT patients underwent ECGI and chest/heart computed tomography 6-24 months of post-implant. Latest electrically activated site and the distance to LVPS (dp) were assessed. Left ventricular end-systolic volume (LVESV) reduction of ≥15% at clinical follow-up defined response. Logistic regression probabilistically modelled non-response; variables included demographics, heart failure classification, left bundle branch block (LBBB), ischaemic heart disease (IHD), atrial fibrillation, QRS duration, baseline ejection fraction (EF) and LVESV, comorbidities, use of CRT optimization algorithm, angiotensin-converting enzyme inhibitor(ACE)/angiotensin-receptor blocker (ARB), beta-blocker, diuretics, and dp. Of 111 studied patients [64 ± 11 years, EF 28 ± 6%, implant duration 12 ± 5 months (mean ± SD), 98% had LBBB, 38% IHD], 67% responded at 10 ± 3 months post CRT-implant. Latest electrically activated sites were outside the mid-to-basal lateral segments in 35% of the patients. dp was 42 ± 23 mm [31 ± 14 mm for responders vs. 63 ± 24 mm non-responders (P < 0.001)]. Longer dp and the lack of use of CRT optimization algorithm were the only independent predictors of non-response [area under the curve (AUC) 0.906]. dp of 47 mm delineated responders and non-responders (AUC 0.931). CONCLUSION: The distance between LV pacing site and latest electrical activation is a strong independent predictor for CRT response. Non-invasive electrical evaluation to characterize intrinsic activation and guide LV lead deployment may improve CRT efficacy.

This article has been withdrawn due to a publisher error that caused the article to be duplicated. The definitive version of this article is published under https://doi.org/10.1093/europace/euaa411.

BACKGROUND: Device patients may require upgrade interventions from simpler to more complex cardiac implantable electronic devices. Prior to upgrading interventions, clinicians need to balance the risks and benefits of transvenous lead extraction (TLE), additional lead implantation or lead abandonment. However, evidence on procedural outcomes of TLE at the time of device upgrade is scarce. METHODS: This is a post hoc analysis of the investigator-initiated multicenter Swiss TLE registry. The objectives were to assess patient and procedural factors influencing TLE outcomes at the time of device upgrades. RESULTS: 941 patients were included, whereof 83 (8.8%) had TLE due to a device upgrade. Rotational mechanical sheaths were more often used in upgraded patients (59% vs. 42.7%, p = 0.015) and total median procedure time was longer in these patients (160 min vs. 105 min, p < 0.001). Clinical success rates of upgraded patients compared to those who received TLE due to other reasons were not different (97.6% vs. 93.0%, p = 0.569). Moreover, multivariable analysis showed that upgrade procedures were not associated with a greater risk for complications (HR 0.48, 95% confidence interval 0.14-1.57, p = 0.224; intraprocedural complication rate of upgraded patients 7.2% vs. 5.5%). Intraprocedural complications of upgraded patients were mostly associated with the implantation and not the extraction procedure (67% vs. 33% of complications). CONCLUSIONS: TLE during device upgrade is effective and does not attribute a disproportionate risk to the upgrade procedure.

INTRODUCTION Long-term complication rates in standard transvenous pacemakers are reported around 4-12% with a higher incidence in the elderly population. We report our experience in octogenarians undergoing leadless pacemaker implantation in two large-volume centers in Switzerland. METHODS Consecutive patients undergoing leadless pacemaker implantation at two Swiss large volume centers (University Hospital Zurich, Zurich and Cardiocentro Ticino Institute, Lugano) between October 2015 and March 2020 were included in this retrospective analysis. Demographic information, clinical data, and procedural characteristics were recorded at the day of implantation and during follow-up. RESULTS Two hundred and twenty patients (mean age 80.6 ± 7.7 years, male 66%) were included. The main indication for pacemaker implantation was slow ventricular rate atrial fibrillation (111 of 220 patients, 50.4%). Out of the 220 patients, 124 (56.3%) were ≥80 years. Overall successful implantation rate was 98.6%. In the octogenarian population, the median procedure time (45 ± 20.2 min vs. 40 ± 19.6 min, p = 0.03) and radiation duration (6.1 ± 8.2 min vs. 5.0 ± 7.2 min, p = 0.03) were longer compared to patients <80 years. Major complications (2.7%, n = 6) and device measurements during follow-up were similar between patients ≥80 and <80 years. CONCLUSION Implantation of a leadless pacemaker device in octogenarians is safe and effective with a similarly low complication rate compared to non-octogenarians.

INTRODUCTION: Data on peri-operative management of direct-acting oral anticoagulants (DOACs) during transcatheter pacing leadless system (TPS) implantations remain limited. This study aimed to evaluate a standardized DOAC management regime consisting of interruption of a single dose prior to implantation and reinitiation within 6-24 h; also, patient clinical characteristics associated with this approach were identified. METHOD: Consecutive patients undergoing standard TPS implantation procedures from two Swiss tertiary centers were included. DOAC peri-operative management included the standardized approach (Group 1A) or other approaches (Group 1B). RESULTS: Three hundred and ninety-two pts (mean age 81.4 ± 7.3 years, 66.3% male, left ventricular ejection fraction 55.5 ± 9.6%) underwent TPS implantation. Two hundred and eighty-two pts (71.9%) were under anticoagulation therapy; 192 pts were treated with DOAC; 90 pts were under vitamin-K antagonist. Patients treated with DOAC less often had structural heart disease, diabetes mellitus, and advanced renal failure. The rate of major peri-procedural complications did not differ between groups 1A (n = 115) and 1B (n = 77) (2.6% and 3.8%, p = 0.685). Compared to 1B, 1A patients were implanted with TPS for slow ventricular rate atrial fibrillation (AF) (p = 0.002), in a better overall clinical status, and implanted electively (<0.001). CONCLUSIONS: Standardized peri-procedural DOAC management was more often implemented for elective TPS procedures and did not seem to increase bleeding or thromboembolic adverse events.

Objective: Evidence on long-term costs of atrial fibrillation (AF) and associated factors is scarce. As part of the Swiss-AF prospective cohort study, we aimed to characterise AF costs and their development over time, and to assess specific patient clusters and their cost trajectories. Methods: Swiss-AF enrolled 2415 patients with variable duration of AF between 2014 and 2017. Patient clusters were identified using hierarchical cluster analysis of baseline characteristics. Ongoing yearly follow-ups include health insurance clinical and claims data. An algorithm was developed to adjudicate costs to AF and related complications. Results: A subpopulation of 1024 Swiss-AF patients with available claims data was followed up for a median (IQR) of 3.24 (1.09) years. Average yearly AF-adjudicated costs amounted to SFr5679 (€5163), remaining stable across the observation period. AF-adjudicated costs consisted mainly of inpatient and outpatient AF treatment costs (SFr4078; €3707), followed by costs of bleeding (SFr696; €633) and heart failure (SFr494; €449). Hierarchical analysis identified three patient clusters: cardiovascular (CV; N=253 with claims), isolated-symptomatic (IS; N=586) and severely morbid without cardiovascular disease (SM; N=185). The CV cluster and SM cluster depicted similarly high costs across all cost outcomes; IS patients accrued the lowest costs. Conclusion: Our results highlight three well-defined patient clusters with specific costs that could be used for stratification in both clinical and economic studies. Patient characteristics associated with adjudicated costs as well as cost trajectories may enable an early understanding of the magnitude of upcoming AF-related healthcare costs. Keywords: Atrial Fibrillation; Health Care Economics and Organizations

Background: Systems for dispatch of volunteer responders to collect automated external defibrillators and/or to provide cardiopulmonary resuscitation (CPR) in cases of nearby out-of-hospital cardiac arrest (OHCA) are widely implemented. Objectives: This study aimed to investigate whether the activation of a volunteer responder system to OHCAs was associated with higher rates of bystander CPR, bystander defibrillation, and 30-day survival vs no system activation. Methods: This was a retrospective observational analysis within the ESCAPE-NET (European Sudden Cardiac Arrest network: Towards Prevention, Education, New Effective Treatment) collaborative research network. Included were cases of OHCA between 2015 and 2019 from 5 European sites with volunteer responder systems. At all sites, systems were activated by dispatchers at the emergency medical communication center in response to suspected OHCA. Exposed cases (system activation) were compared with nonexposed cases (no system activation). Risk ratios (RRs) were calculated for the outcomes of bystander CPR, bystander defibrillation, and 30-day survival after inverse probability treatment weighting. Missing data were handled using multiple imputation. Results: In total, 9,553 cases were included. In 4,696 cases, the volunteer responder system was activated, and in 4,857 it was not. The pooled RRs were 1.30 (95% CI: 1.15–1.47) for bystander CPR, 1.89 (95% CI: 1.36–2.63) for bystander defibrillation, and 1.22 (95% CI: 1.07–1.39) for 30-day survival. Conclusions: Activation of a volunteer response system in cases of OHCA was associated with a higher chance of bystander CPR, bystander defibrillation, and 30-day survival vs no system activation. A randomized controlled trial is necessary to determine fully the causal effect of volunteer responder systems.