Device Size Research Articles

Innovative Ultralow Thermal Budget ZrHfOx Ferroelectric Films with Low-Temperature Phase Transition for Next-Generation High-Speed Multifunctional Devices.

By design of the element concentration, regulating the ratio of the t phase and the energy difference between t and o phases, the ZrHfOx (ZHO) film demonstrated the highest polarization value at a maximum processing temperature of only 280 °C without an annealing process, and it can withstand over 1010 polarization cycles without breakdown. The ZHO film maintains good ferroelectric performance in extreme temperature environments (4.55 to 473 K). Even under high-temperature conditions, the ZHO film shows exceptional endurance performance (>1010 at 423 K). These parameters represent the best overall performance reported in the literature to date. The polarization switching process can be accurately described by the nucleation limited switching (NLS) model, and the polarization switching time is expected to reach the sub-ns level as the device size decreases. The ZHO film demonstrates great potential in both process simplification and performance optimization, providing new possibilities for the application of ferroelectric devices.

Optimal sizing and placement of STATCOM, TCSC and UPFC using a novel hybrid genetic algorithm-improved particle swarm optimization

The increase in global power demand has caused most of today's power networks to become overloaded especially in Sub-Saharan Africa. The increased load demand can be met through expansion of existing generation and transmission system. However, construction of new power infrastructure is limited by financing and technical constraints. Thus, power networks have been left to operate at overload conditions with high power losses and many power quality (PQ) problems. Flexible AC Transmission System (FACTS) devices can improve the power transfer capability of the existing transmission networks without the need of constructing new power infrastructure. In this paper, a multi-objective function comprising of minimization of power loss (PL), voltage deviation (VD) and operational cost (OC) was formulated and solved using a novel algorithm. A novel Genetic Algorithm-Improved Particle Swarm Optimization (GA-IPSO) technique is proposed in this paper for optimization of size and location of FACTS devices. Static Synchronous Compensator (STATCOM), Thyristor Controlled Series Capacitor (TCSC) and Unified Power Flow Controller (UPFC) are the three FACTS devices considered. The proposed technique was validated using IEEE-33 Bus Test System, which is a popular benchmark Radial Distribution System (RDS). The three FACTS devices were optimized separately and also in a combined manner. Under the separate optimization, the size and location of individual FACTS devices were optimized. For combined optimization, the sizes and locations of more than one device were optimized in the same test system. For separate optimization, UPFC produced the best results by reducing the active power losses by 38.44 % and OC from $1.59×105 to $ 1.15×105. Under the combined optimization, combination of TCSC, STATCOM and UPFC gave better results by achieving active power loss reduction of 56.09 % and reducing OC from $1.59×105 to $ 1.03×105. Comparison of GA-IPSO technique with other algorithms such as Particle Swarm Optimization (PSO), Genetic Algorithm (GA), Improved Grey Wolf Optimization (IGWO) and Differential Evolution Algorithm (DEA) showed that the proposed hybrid technique was superior and more efficient in solving the FACTS optimization problem.

Patients' perceptions of nocturnal erectile function assessment with the RigiScan®.

In recent decades, the assessment of male sexual function has been a subject of enduring interest. The use of the RigiScan®, a conventional diagnostic tool designed to differentiate between psychological and organic causes of erectile dysfunction (ED), has decreased due to several disadvantages. In this study, patient perspectives on the merits and drawbacks of the RigiScan®, as well as preferences for a future diagnostic device, were explored. Patients at St. Antonius Hospital and Leiden University Medical Center who underwent RigiScan® examinations were surveyed. A pretested questionnaire was used to gather data on their experiences, satisfaction levels, and suggestions for improvement. Among the 120 distributed questionnaires, a 39.2% response rate was achieved. The process of applying the RigiScan® around the penis was reported to have an average difficulty rating of 4.6 ± 2.5 (range: 1-9) points. While 74.5% of the participants were able to keep the device on all night, 25.5% of the participants experienced difficulties. Sleep quality was assessed at 5.5 ± 2.6 (range: 0-9) points. The participants reported an average pain rating of 4.7 ± 2.8 (range: 0-9) points. Despite these challenges, 69.6% of the participants reported that the device met their expectations, while 30.4% of the participants were dissatisfied. The key areas for improvement included device size (33.7%), user-friendliness (25.5%), sound (9.2%), hygiene (7.1%), and pain (6.1%). This study revealed that patients who underwent a nocturnal erectile function assessment with the RigiScan® device preferred a more patient-friendly and less intrusive diagnostic device. Further research is needed to determine whether a new sensor possessing these improved characteristics can increase patient satisfaction.

Visualizing Performances Losses of Perovskite Solar Cells and Modules: From Laboratory to Industrial Scales

AbstractWhile the efficiencies of lab‐sized perovskite solar cells are continuously rising, a variety of challenges have to be overcome to realize remotely similar efficiencies in an industrial context. Any changes in the preparation process, device size, device architecture, and material type are likely to result in efficiency loss. To date, there have been no solutions that can produce large‐area modules with performance comparable to that of laboratory devices. However, depending on the type of deposition process, the dominant loss mechanisms differ significantly, which can guide the further optimization of processes and devices. In this study, a meta‐analysis of state‐of‐the‐art perovskite solar cells and modules with different preparation methods, area sizes, and material compositions, is presented. Moreover, the efficiency losses are divided into five figures of merit and they are visualized to discuss the efficiency‐limiting loss mechanisms that must be overcome for commercialization.

A Fully Integrated Orthodontic Aligner With Force Sensing Ability for Machine Learning-Assisted Diagnosis.

Currently, the diagnosis of malocclusion is a highly demanding process involving complicated examinations of the dental occlusion, which increases the demand for innovative tools for occlusal data monitoring. Nevertheless, continuous wireless monitoring within the oral cavity is challenging due to limitations in sampling and device size. In this study, by embedding high-performance piezoelectric sensors into the occlusal surfaces using flexible printed circuits, a fully integrated, flexible, and self-contained transparent aligner is developed. This aligner exhibits excellent sensitivity for occlusal force detection, with a broad detection threshold and continuous pressure monitoring ability at eight distinct sites. Integrated with machine learning algorithm, this fully integrated aligner can also identify and track adverse oral habits that can cause/exacerbate malocclusion, such as lip biting, thumb sucking, and teeth grinding. This system achieved 95% accuracy in determining malocclusion types by analyzing occlusal data from over 1400 malocclusion models. This fully-integrated sensing system, with wireless monitoring and machine learning processing, marks a significant advancement in the development of intraoral wearable sensors. Moreover, it can also facilitate remote orthodontic monitoring and evaluation, offering a new avenue for effective orthodontic care.

Enhanced Readout Reliability in Phase Change Memory with a Dual-Sensing-Margin Offset-Compensated Sense Amplifier

Phase change memory (PCM) is considered one of the most promising candidates for next-generation non-volatile memory, owing to its scalability, durability, and cost-effectiveness. However, with the shrinking of device sizes and the reduction in supply voltages, achieving high-speed and reliable readouts in PCM has become increasingly challenging due to process variations. To address this, the dual-sensing-margin offset-compensated sense amplifier (DSOC-SA) is proposed. The DSOC-SA achieves the highest sensing margin, and the lowest read energy consumption compared to traditional sense amplifiers by utilizing a dual-sensing-margin structure, offset compensation, and strong positive feedback. Simulation results demonstrate that, compared to differential sense amplifier and offset-canceling current-sampling sense amplifier, DSOC-SA achieves a 5.6× and 1.6× improvement in sensing speed, respectively, while reducing power consumption by 87.1% and 51.2%.

Self-catalyzed growth of sub-25-nm-diameter InAs nanowire arrays on Si patterned substrate

The feature size of advanced Si-based chips is approaching its physical limit, and it is difficult to continue Moore's Law by simply pursuing the technical route of miniaturizing device size to increase the integrated density. III-V nanowire devices represented by InAs material have much higher mobility than Si based devices, but they have not been successfully applied to CMOS nanowire devices and have not shown excellent performance. The reason is that the hole mobility of III-V materials is much lower than their electron mobility. If the nanowire diameter becomes ultrafine, the quantum confinement effect becomes more prominent, the light hole band will reverse above the heavy hole band, and the hole mobility will be greatly increased. Aiming at the integrability of III-V high mobility CMOS devices on Si, how to prepare ultrafine InAs nanowire arrays on Si/SiO2 patterned substrates has been studied in this work. New method in this work has solved the problem that the nanohole will enlarge due to etching side wall of nanohole by HF process before growth. A technology and mechanism of ultrafine InAs nanowire arrays grown by this method was developed, and the smallest diameter of nanowire in array has reached only 25 nm.

Mid-infrared arrayed waveguide gratings using a quantum cascade laser gain medium as core material

Mid-infrared photonics is a widely researched field with several applications, such as chemical sensing and spectroscopy. The development of photonic integrated circuits for the mid-infrared can enable the reduction in device size, weight, and power (SWaP) consumption. This paper demonstrates arrayed waveguide gratings working in the mid-infrared regime (5–5.4 µm). Our devices are fabricated on an InP-based quantum cascade laser platform with the gain medium as the waveguide core. To minimize the propagation losses caused by free carrier absorption and intersubband absorption in the unbiased QCL structure, we exposed the photonic chips to proton implantation. The performance of three sets of AWGs with different etch depths was characterized. The lowest waveguide losses were measured to be 2 dB/cm. The best performing 7×1 AWG and 13×1 AWG designs featured insertion losses of −2dB and −2.5dB, respectively. This study showcases the feasibility of applying such a platform for easy integration with active components like lasers and photodetectors, paving the path for on-chip mid-infrared applications.

Abstract 4129839: Successful Left Atrial Appendage Occlusion (LAAO) with WATCHMAN FLX via Transhepatic Approach

Left atrial appendage occlusion (LAAO) with the WATCHMAN FLX (Boston Scientific) has been proven to reduce stroke risk in patients with paroxysmal atrial fibrillation (PAF). Certain circumstances may preclude LAAO1. In this case, transhepatic vein access was used to successfully deploy a WATCHMAN FLX in a 72 year old male with PAF not on anticoagulation due to recent subdural hemorrhage and recurrent bilateral lower extremity deep venous thrombosis (DVT) post IVC filter placement. Recent attempt at LAAO was unsuccessful due to total occlusion of bilateral femoral veins (Figure 1 A-B) and inability to cross the IVC. Access to the inferior branch of the right hepatic vein was achieved by micropuncture technique at the right mid-axillary line at the level of the 12th rib, which was confirmed by venogram (Figure 2A). The 4F microsheath was upsized to 16F. Intraoperative TEE was used for device sizing and delivery (Figure 3A). The transseptal sheath and dilator were positioned in the right atrium at the level of the fossa ovalis (Figure 3B) before successfully crossing into the left atrium (Figure 2B). After confirming placement (Figure 3C), a pigtail catheter was positioned within the LAA (Figure 3D) and an angiogram was performed (Figure 2C). A 24 mm WATCHMAN FLX was partially unsheathed and positioned (Figure 3E). Repeat LAA angiogram was performed through the WATCHMAN delivery sheath (Figure 2D). A Tug test was performed. The device was released (Figure 3F). Repeat venogram was performed to confirm location (Figure 2E) of the access site, and coil embolization closure of the venotomy access site was performed (Figure 2F). The patient was discharged the following day on dual antiplatelet (aspirin, clopidogrel) without complication. Venous access via right hepatic vein is a viable option for LAAO using the WATCHMAN FLX device.

Two-Stage Optimization of Mobile Energy Storage Sizing, Pre-Positioning, and Re-Allocation for Resilient Networked Microgrids with Dynamic Boundaries

Networked microgrids (NMGs) enhance the resilience of power systems by enabling mutual support among microgrids via dynamic boundaries. While previous research has optimized the locations of mobile energy storage (MES) devices, the critical aspect of MES capacity sizing has been largely neglected, despite its direct impact on costs. This paper introduces a two-stage optimization framework for MES sizing, pre-positioning, and re-allocation within NMGs. In the first stage, the capacity sizing and pre-positioning of MES devices are optimized before a natural disaster. In the second stage, the re-allocation and active power output of MES devices are adjusted post-disaster, with boundary switches operated based on the damage scenarios. The framework restores unserved loads by either forming isolated microgrids using MES or re-establishing connections between microgrids via smart switches. The proposed framework is modeled mathematically and solved using a customized progressive hedging algorithm. Extensive experiments on modified IEEE 33-node and 69-node systems demonstrate the model’s effectiveness and applicability in improving system resilience.

Analysis of Gain Enhancement Techniques in Integrated Circuit Design

Abstract. Today, the size of semiconductor devices is still decreasing, which makes the circuit more integrated, faster computing speed, and lower power consumption. But for a single transistor, some performance degrades. One of the important properties is voltage gain, which must be compensated with some special methods in the design. This paper will focus on the discussion and analysis of four methods, which are able to improve the voltage gain. These are cascode amplifier, cascade amplifier, gain boosting, and bootstrapping. In this letter, their respective advantages and disadvantages will be discussed. Furthermore current applications and possible external development of these methods are also important part of this paper. In this part, the discussion will be further expanded and summarized on the basis of previous studies. Hopefully, these studies can help others gain a more comprehensive understanding of these technologies and provide a theoretical basis for future high-performance analog integrated operational amplifier research and design.

The Role of Tissue Expansion Before Baclofen Pump Insertion in the Pediatric Population.

Tissue expansion is a well-established technique for soft tissue reconstruction in the pediatric population. We present a case series of this technique to create a safe pocket for baclofen pump insertion to minimize risk of complications including pump migration, extrusion, wound dehiscence and infection. A case series of 3 pediatric patients undergoing tissue expansion prior to baclofen pump insertion at a single center in Melbourne. The expansion procedure was performed by senior surgeon N Low in all cases, and patients followed up 6 months after expander-pump exchange. The study was conducted over a 4-year period 2019 to 2023. We suffered 2 minor complications with the tissue expansion process including cellulitis and pump deflation. Neither complication precluded further tissue expansion nor led to premature removal of the expander. All patients proceeded to safely complete expander-pump exchange. One patient suffered a small (6 mL) abdominal seroma associated with pump insertion, which required no intervention. All patients have had a successful outcome 6 months after pump insertion. We describe a reliable and reproducible approach in creating a safe abdominal wall pocket to better accommodate baclofen pump insertion. Our series has overcome the imbalance between device size and abdominal wall pocket, now offering an alternative approach to achieve the safe delivery of intrathecal baclofen in the pediatric population.

Ultrahigh quality factor cavity based on double dielectric nanocylinder metasurfaces

An optical cavity with a high quality factor (Q-factor) is essential for a wide range of applications, including lasers, single-photon sources, optical filters, and sensors. A high Q-factor cavity can enhance the interaction between light and materials, thereby improving the performance of optical devices. The Fabry–Pérot (FP) cavity is a typical optical device capable of achieving a high Q-factor; however, it often relies on distributed Bragg reflectors, which increase the size of the optical device. In recent years, Mie scattering-based metasurfaces with high reflectivity have been studied as alternatives to distributed Bragg reflectors. We propose a scattering-based FP cavity consisting of two metasurface layers. In our structure, a FP cavity with high reflectivity is formed by back-forward scattering from a single dielectric cylinder array. Our findings show that the structure exhibits a Q-factor of 4.36 × 1010 when the period and gap size are 658.8 nm and 740 nm, respectively. This high Q-factor is maintained even with misalignment between the two layers. Additionally, we confirmed that a high Q-factor of 2.6 × 106 appears in the low-index substrate structure, with the Q-factor increasing with the number of double cylinders in the finite structure. We also observed a strong directionality in the z-axis direction when examining the far field. We designed the dielectric FP cavity with a subwavelength thickness, is expected to significantly contribute to enhancing the Q-factors of various types of optical cavities.

Fully Printed Multilayer Ceramic Capacitors Based on High-k Perovskite Nanosheets.

Printing technology enables the integration of chemically exfoliated perovskite nanosheets into high-performance microcapacitors. Theoretically, the capacitance value can be further enhanced by designing and constructing multilayer structures without increasing the device size. Yet, issues such as interlayer penetration in multilayer heterojunctions constructed using inkjet printing technology further limit the realization of this potential. Herein, a series of multilayer configurations, including Ag/(Ca2NaNb4O13/Ag)n and graphene/(Ca2NaNb4O13/graphene)n (n = 1-3), are successfully inkjet-printed onto diverse rigid and flexible substrates through optimized ink formulations, inkjet printing parameters, thermal treatment conditions, and rational multilayer structural design using high-k perovskite nanosheets, graphene nanosheets and silver. The dielectric performance is optimized by fine-tuning the number of dielectric layers and modifying the electrode/dielectric interface. As a result, the graphene/(Ca2NaNb4O13/graphene)3 multilayer ceramic capacitors exhibit a remarkable capacitance density of 346±12nFcm-2 and a high dielectric constant of 193±18. Additionally, these devices demonstrate moderate insulation properties, flexibility, thermal stability, and chemical sensitivity. This work shed light on the potential of multilayer structural design in additive manufacturing of high-performance 2D material-based ceramic capacitors.

Procedural success and complications of transthoracic echocardiography guided atrial septal defect device closure in children at a tertiary cardiac centre in Nepal

BackgroundAlthough transthoracic echocardiography (TTE) is easy and more widely available with excellent acquisitions in children, there are limited evidence regarding its use in guiding transcatheter closure of ASD. ObjectivesWe aimed to evaluate the safety, feasibility, and outcome of transcatheter closure of ASD in children guided by TTE in combination with fluoroscopy. MethodsAll children aged 4–15 years who were considered for and underwent transcatheter ASD closure of ASD Secundum type under TTE and fluoroscopy guidance at the National Heart Centre in Kathmandu, Nepal from August 2018 through May 2021, were retrospectively reviewed. ResultsOf the 94 children, transcatheter closure was attempted in only 89 patients, and implantation of device was successful in all of them (100 %). The procedure was done under total intravenous anesthesia in 79.8 % of children, and local anesthesia in the rest. The ASD size varied between 7 and 32 (15.2 ± 5.8) mm. ASDs were closed using the device size ranged between 10 and 38(19.2 ± 1) mm. The mean of device/patient weight and device/ASD size ratio were 82 ± 0.33 and 1.28 ± 0.25 respectively. Similarly mean duration of procedure and fluoroscopy was being 31.2 ± 8.6 and 6.5 ± 2.8 min respectively. Five children (5.6 %) had tiny residual shunt which closed spontaneously as documented by TTE within 6 months after the procedure. A new onset atrial tachycardia was detected in one child during follow up. Otherwise, we observed no major early postprocedural or late complications during follow up period of 18.4 ± 8.5 months. ConclusionTTE is a safe and feasible guiding tool in children with adequate acoustic windows for the deployment of the ASD device under fluoroscopy.

A Study on Ways to Expand the Speed Operation Range of Dental Laboratory Handpiece Motors Using Low-Cost Hall Sensors

In the dental prosthetics field, BLDC micro-motors are primarily used for implant procedures. As dental materials become increasingly harder, there is a growing demand for higher performance motors to precisely process these materials. However, difficulties in motor development arise due to price competitiveness. Dental motors require capabilities such as low-speed, high-torque for drilling operations and high-speed rotation for precise machining of high-strength dental materials. Additionally, there is a requirement to address thermal issues to prevent user burns due to motor-generated heat. Typically, motors requiring precision control utilize high-resolution position sensors like encoders or resolvers to acquire and control the rotor’s position. However, the high cost of these sensors and constraints such as increased device size pose challenges in maintaining price competitiveness. In this paper, we propose a control algorithm that satisfies the requirements for low-speed, high-torque and high-speed operation requirements for precision machining without hardware modifications using a BLDC micro-motor equipped with an inexpensive Hall sensor commonly used in the dental field. Furthermore, the algorithm is designed to ensure stable operation even in the event of Hall sensor failure or malfunction, and its effectiveness is validated through experiments.

Flexible highly-sensitive pressure sensor based on rGO/Fe nanowires composites for wearable human health detection.

Flexible pressure sensors applied in wearable detection often face challenges, such as low sensitivity, large device size, poor flexibility, and long response time. This study aims to design and develop high-performance pressure-sensitive materials for wearable human detection applications. Using a sensitive layer composite and microstructural design, rGO/Fe nanowires (NWs) composites were proposed as the pressure-sensitive material. This approach yields a compact sensor with high flexibility, good mechanical properties, and excellent sensing performance. Firstly, rGO/Fe NWs composites were prepared by the Hummers method and an in situ reduction technique under a magnetic field. Secondly, the structural design, component construction, and sensing mechanism of the sensors were thoroughly investigated. Finally, the performance of the flexible pressure sensor was tested, and its application in the wearable field was explored. The results demonstrate that the sensor exhibits excellent performance with a good response to both large and small pressures within the range of 0-30kPa, providing an effective method for wearable human health detection.

Combined PVI and LAAC is feasible using RFA or PFA in a canine model despite acute tissue edema in PFA versus RFA

Abstract Background Combined procedure with pulmonary vein isolation (PVI) using thermal energy followed by left atrial appendage closure (LAAC) has been used in select patient populations with positive results. Pulsed field ablation (PFA) is a novel non-thermal ablation modality that ablates cardiac tissue by irreversible electroporation. The effect of PFA on cardiac tissue and its interaction with a LAAC device in a single procedure has not been studied. Purpose To evaluate using transesophageal echo (TEE) imaging the acute tissue response following ablation by PFA compared to radiofrequency ablation (RFA) and its interaction with the WATCHMAN FLX Pro LAAC device when used in a combined procedure in a healthy canine model. Methods Nine mongrel canines underwent PVI using either circumferential PFA (FARAPULSE) energy application (n=6) or RFA energy (n=3). TEE imaging was obtained at the time of the procedure before and immediately after ablation energy application. The general appearance and echogenicity of the left lateral ridge was assessed and the os of the left atrial appendage (LAA) was measured in the four standard TEE views (0, 45, 90, and 135 degrees). Decisions about device sizing were made accordingly. PVI was evaluated by entry and exit block in all veins except the right inferior pulmonary vein (RIPV), which was not ablated. Following ablation, the LAAC device was implanted using TEE and fluoroscopic guidance in all animals and the percentage of compression measured. PASS criteria were assessed before the release of each device. All animals received dual antiplatelet therapy post implant. Results PVI was confirmed in all animals (except RIPV which was not targeted for ablation) using PFA and RFA. LAA dimensions (at device landing site) did not change substantially after RF ablation. With PFA, there was evidence of more diffuse edema and decrease in LAA diameter (Table). The LAAC device was implanted successfully after meeting PASS criteria in all animals within 30 minutes post ablation. The device size was decreased following PFA in two (2/6) animals, whereas there was no deviation from baseline measurements in device size for any of the RFA animals. Average LAAC device compression was higher for PFA versus RFA animals (Table). TEE post implant confirmed absence of any peri-device leaks in all animals. Conclusion Concomitant PVI using PFA (FARAPULSE) and LAAC (WATCHMAN FLX Pro) is feasible with 100% success and no residual acute peri-device leak. In the canine model, PFA is associated with more diffuse edema compared to RFA, which might affect device sizing. Long term consequences of this acute edema need to be evaluated in serial imaging and future larger clinical trials.Table

Feasibility, accuracy, and reproducibility of device sizing in virtual reality for percutaneous left atrial appendage closure - a single center study

Abstract Background Left atrial appendage closure (LAAC) is a safe and effective procedure for stroke prevention in patient with non-valvular atrial fibrillation. Procedural planning and device sizing remains challenging due to the highly complex and variable three-dimensional (3D) anatomy of the left atrial appendage (LAA). Virtual reality (VR) is a innovative, recent technology allowing a superior spatial orientation visualization of 3D imaging datasets. Purpose Therefore, we aimed to evaluate feasibility and accuracy of LAA measurements in VR for device sizing in patients planned for LAAC. Methods Twenty-one patients (79±7 years, 62% male) with non-valvular atrial fibrillation scheduled for LAAC were randomly included in our study. Preprocedural a multi-slice computed tomography (MSCT) was performed for device sizing in all patients. MSCT-based 3D models were established and visualized in VR using a dedicated software (VMersive, Warsaw, Poland). LAA dimensions (Ostium, landing zone (LZ), and depth) were assessed directly in the virtual environment. Conventional measurements of LAA ostium, landing zone (LZ) and depth using commercially available software were compared to measurements in VR. Results 3D reconstruction of MSCT datasets and visualization in VR were successfully performed automatically in all patients within a few seconds. MSCT and VR demonstrated good correlations for ostium minimum (r = 0.93), maximum (r = 0.8) and mean (r = 0.88, all p<0.001) diameters. Additionally, LZ minimum (r=0.84), maximum (r=0.86) and mean (r=0.9) diameters showed good correlation (all p<0.001). Moderate correlation was observed for depth measurements (r=0.76, p<0.001). Furthermore, intraclass correlation coefficients ranging from 0.88 to 0.98 denoted high inter- and intraobserver agreement. Conclusion Immersive VR allows highly feasible, accurate and reproducible measurements of the LAA dimensions directly in the virtual environment, hence enabling accurate device sizing for LAAC.

Safety and efficacy of perventricular device closure of ventricular septal defects in children

Abstract Objectives To evaluate safety and efficacy of perventricular device closure techniques for the closure of ventricular septal defects (VSD) in children in United Arab Emirates. Methods In the year 2023-24, 13 children underwent per-ventricular device closures of VSD under the guidance of transesophageal echocardiography without cardiopulmonary bypass(CPB). The mean age at operation was 3.76 years (range 3 months-14 years). The ventricular septal defect sizes ranged from 2.7-6 mm. The device sizes ranged from 5-12mm. All patients except two required symmetrical device. Eight defects were peri membranous, 3 were sub-aortic and 2 were muscular. Ventricular septal defect occlusion device (Memoport, Beijing, China) were used through a 3-cm skin incision in the lower third of the sternum. Results All patients underwent VSD device closure successfully. The mean procedural duration was 42 minutes. None of the patients required CPB. The mean ventilation time and ICU stay was 3 hrs. and 24 hrs. respectively. None of the patients required inotropic support or blood transfusions. There were no residual shunt (except small shunt through the device), arrhythmias including heart block post operatively. At follow up, (3 months-7 months) there were no residual shunts, conduction disturbances, device dislodgement or major aortic or tricuspid valve complications. There was no mortality. Conclusions Perventricular device closure of VSD is highly successful, less invasive, safe and effective. It is associated with quick recovery, short length of stay and better cosmetic incision. Moreover, it avoids CPB.