Ventricular Dyssynchrony and Pacing-induced Cardiomyopathy in Patients with Pacemakers, the Utility of Ultra-high-frequency ECG and Other Dyssynchrony Assessment Tools

The majority of patients tolerate right ventricular pacing well; however, some patients manifest signs of heart failure after pacemaker implantation and develop pacing-induced cardiomyopathy. This is a consequence of non-physiological ventricular activation bypassing the conduction system. Ventricular dyssynchrony was identified as one of the main factors responsible for pacing-induced cardiomyopathy development. Currently, methods that would allow rapid and reliable ventricular dyssynchrony assessment, ideally during the implant procedure, are lacking. Paced QRS duration is an imperfect marker of dyssynchrony, and methods based on body surface mapping, electrocardiographic imaging or echocardiography are laborious and time-consuming, and can be difficult to use during the implantation procedure. However, the ventricular activation sequence can be readily displayed from the chest leads using an ultra-high-frequency ECG. It can be performed during the implantation procedure to visualise ventricular depolarisation and resultant ventricular dyssynchrony during pacing. This information can assist the electrophysiologist in selecting a pacing location that avoids dyssynchronous ventricular activation

Dispersión espacial de los tiempos de activación y repolarización asociada a diferentes modos de estimulación cardiaca

En pacientes con indicación de marcapasos permanente se aplican distintos tipos de estimulación ventricular. Los denominados fisiológicos estimulan el sistema de conducción cardiaca induciendo una activación fisiológica eficiente. Entre estos se encuentran la estimulación selectiva del haz de His (HBP selectiva, sHBP, y HBP no selectiva, nsHBP, por sus siglas en inglés) y las estimulaciones selectiva y no selectiva de la rama izquierda (sLBBP y nsLBBP) Otras regiones cardiacas que también suelen estimularse mediante el marcapasos son el septo del ventrículo izquierdo (LVSP) o del ventrículo derecho (RVSP) y el ápex del ventrículo derecho (RVAP). En este trabajo se analizaron 695 electrocardiogramas de muy alta frecuencia (UHF-ECG) obtenidos de 176 pacientes con complejo QRS estrecho y con indicación de marcapasos. Se caracterizaron los tiempos de activación (TA) y de repolarización (TR) y se agruparon en tres regiones según las derivaciones en las que se evaluaron (R1: derivaciones V1-V2; R2: V3-V4; R3: V5-V6). Globalmente en la población, las estimulaciones sHBP, nsLBBP y LVSP proporcionaron los valores de AT y RT más similares a los obtenidos durante ritmo espontáneo. Los valores absolutos de las medias para las diferencias R1-R2 y R3-R2 en TA resultaron menores a 3, 16 y 10 ms para sHBP, nsLBBP y LVSP, respectivamente, con respecto al ritmo espontáneo. Para TR estas diferencias fueron menores a 11, 34 y 24 ms para sHBP y nsLBBP y LVSP. En conclusión, las estimulaciones HBP, LBBP y LVSP inducen los tiempos de activación y repolarización ventricular más similares a los hallados en ritmo espontáneo en pacientes con conducción fisiológica (QRS estrecho).Este trabajo ha sido realizado con el apoyo de los proyectos PID2019-105674RB-I00, PID2019-104881RB-I00, TED2021-130459B-I00 y la ayuda BES-2017-080587 (Ministerio de Ciencia e Innovación), el proyecto LMP94_21 y el grupo de referencia BSICoS T39-23R (Gobierno de Aragón cofinanciado por el FEDER 2014-2020 “Construyendo Europa desde Aragón”) y el proyecto ERC G.A. 638284 (European Research Council). Los cálculos computacionales se han realizado en la ICTS NANBIOSIS (HPC Unit at University of Zaragoza)

Testing for the MMX Rover Autonomous Navigation Experiment on Phobos

The MMX rover will explore the surface of Phobos, Mars´ bigger moon. It will use its stereo cameras for perceiving the environment, enabling the use of vision based autonomous navigation algorithms. The German Aerospace Center (DLR) is currently developing the corresponding autonomous navigation experiment that will allow the rover to efficiently explore the surface of Phobos, despite limited communication with Earth and long turn-around times for operations. This paper discusses our testing strategy regarding the autonomous navigation solution. We present our general testing strategy for the software considering a development approach with agile aspects. We detail, how we ensure successful integration with the rover system despite having limited access to the flight hardware. We furthermore discuss, what environmental conditions on Phobos pose a potential risk for the navigation algorithms and how we test for these accordingly. Our testing is mostly data set-based and we describe our approaches for recording navigation data that is representative both for the rover system and also for the Phobos environment. Finally, we make the corresponding data set publicly available and provide an overview on its content

Asparagine levels in the cerebrospinal fluid of children with acute lymphoblastic leukemia treated with pegylated-asparaginase in the induction phase of the AIEOP-BFM ALL 2009 study

Asparagine levels in cerebrospinal fluid and serum asparaginase activity were monitored in children with acute lymphoblastic leukemia treated with pegylated-asparaginase. The drug was given intravenously at a dose of 2,500 IU/m2 on days 12 and 26. Serum and cerebrospinal fluid samples obtained on days 33 and 45 were analyzed centrally. Since physiological levels of asparagine in the cerebrospinal fluid of children and adolescents are 4-10 μmol/L, in this study asparagine depletion was considered complete when the concentration of asparagine was ≤0.2 μmol/L, i.e. below the lower limit of quantification of the assay used. Over 24 months 736 patients (AIEOP n=245, BFM n=491) and 903 cerebrospinal fluid samples (n=686 on day 33 and n=217 on day 45) were available for analysis. Data were analyzed separately for the AIEOP and BFM cohorts and yielded superimposable results. Independently of serum asparaginase activity levels, cerebrospinal fluid asparagine levels were significantly reduced during the investigated study phase but only 28% of analyzed samples showed complete asparagine depletion while relevant levels, ≥1 μmol/L, were still detectable in around 23% of them. Complete cerebrospinal fluid asparagine depletion was found in around 5-6% and 33-37% of samples at serum asparaginase activity level

Mobility on the Surface of Phobos for the MMX Rover - Simulation-aided Movement planning

The MMX Rover, recently named IDEFIX, will be the first wheeled robotic system to be operated in a milli-g environment. The mobility in this environment, particularly in combination with the interrupted communication schedule and the activation of on-board autonomous functions such as attitude control requires efficient planning. The Mobility Group within the MMX Rovers Team is tasked with proposing optimal solutions to move the rover safely and efficiently to its destination so that it may achieve its scientific goals. These movements combine various commands to the locomotion system and to the navigation systems developed by both institutions. In the mission's early phase, these actions will rely heavily on manual driving commands to the locomotion system until the rover behavior and environment assumptions are confirmed. Planning safe and efficient rover movements is a multi-step process. This paper focuses on the challenges and limitations in sequencing movements for a Rover on Phobos in the context of the MMX Mission. The context in which this process takes place is described in terms of available data and operational constraints

Interaction with virtual crowd in Immersive and semi‐Immersive Virtual Reality systems

This study examines attributes of virtual human behavior that may increase the plausibility of a simulated crowd and affect the user's experience in Virtual Reality. Purpose-developed experiments in both Immersive and semi-Immersive Virtual Reality systems queried the impact of collision and basic interaction between real-users and the virtual crowd and their effect on the apparent realism and ease of navigation within Virtual Reality (VR). Participants' behavior and subjective measurements indicated that facilitating collision avoidance between the user and the virtual crowd makes the virtual characters, the environment, and the whole Virtual Reality system appear more realistic and lifelike. Adding basic social interaction, such as verbal salutations, gaze, and other gestures by the virtual characters towards the user, further contributes to this effect, with the participants reporting a stronger sense of presence. On the other hand, enabling collision avoidance on its own produces a reduced feeling of comfort and ease of navigation in VR. Objective measurements showed another interesting finding that collision avoidance may reduce the user's performance regarding their primary goal (navigating in VR following someone) and that this performance is further reduced when both collision avoidance and social interaction are facilitated