Low Voltage Research Articles

Xanthan gum biopolymer gated low voltage-operating photo synaptic organic field-effect transistor for neuromorphic electronics

Low voltage-operating light-stimulated organic field effect transistors (OFETs) are attracting huge attention due to their potential for developing photonic neuromorphic synapse-based neural networks resembling the human brain. The OFETs based on environment friendly biocompatible materials and processability are highly desired for realizing photo synaptic elements. In this report, we demonstrate a low voltage operating xanthan gum-gated poly(2,5-bis(3-alkylthiophen-2-yl) thieno[3,2-b] thiophene) [PBTTT-C14] based OFETs, exhibiting photo synaptic behavior at −0.3V. The basic photo response parameters such as photoresponsivity, detectivity, and photocurrent to dark current ratio of the OFETs are estimated to quantify the photo synaptic behavior of the OFETs. We report the fundamental neurobiological characteristics such as excitatory post-synaptic current (EPSC), pair pulse facilitation (PPF), short-term plasticity (STP), long-term plasticity (LTP), learning-forgetting-memorizing (LFM), and conversion of STP to LTP for the xanthan gum-gated PBTTT-C14-based OFETs. Furthermore, we showcase the electronic "OR" logic operations by employing the OFETs and replicate the Pavlovian conditioning experiment to mimic the classical learning phenomenon. Using these photo synaptic OFETs, we replicate human emotion and mood-swing-dependence learning and memory behavior which is an important aspect of cognitive learning. The OFETs exhibit fairly low energy consumption ~100 pJ per optical operation to perform synaptic responses. We interpret and attribute the observed neuromorphic behavior to the charge-trapping occurring at the semiconductor-dielectric interface and bulk traps in OFETs. The presented phenomena broaden opportunities to the device communities for building an artificial complex neural network using energy-efficient bio-polymer gated photo synaptic OFETs.

Optimizing Voltage for Effective X-ray Computed Tomography Scan: A Study on Varied Soil Bulk Densities and Container Sizes

Numerous studies have highlighted the role of X-ray computed tomography (X-ray CT) in understanding root architecture. Nevertheless, setting definitive scanning parameters for diverse soils in varied container sizes remains challenging. This study investigates the influence of X-ray CT system voltage on the penetration capability in diverse soils and container sizes, focusing on two key parameters: (1) gray values, which indicate X-ray attenuation and contribute to image contrast, and (2) signal-to-noise ratio, a measure of image clarity. Five soil samples were collected from various depths within a soil profile to encompass bulk density values ranging from 1.34 to 1.84 g·cm−3 to conduct the experiment. Containers with dimensions of 6 × 6 × 6 cm³, 8 × 8 × 6 cm³, 10 × 10 × 6 cm³, 12 × 12 × 6 cm³, 14 × 14 × 6 cm³, and 16 × 16 × 6 cm³ were used. Voltage levels spanning 75 to 225 kV, in 25-kV increments, were applied to each sample. The observed gray values of the X-ray images were fitted using a logistic model of three parameters. Results showed that increasing voltage leads to enhanced penetration up to a plateau point, irrespective of soil density or container size. This plateau could potentially yield higher quality scans, given that lower voltages result in subdued gray values and reduced image contrast. Notably, it was observed that soil properties, including mineral composition, directly affect image gray values. This study established optimal voltage settings for specific soil types at fixed densities, offering valuable insights for researchers investigating soil–root interactions. Although the current findings are based on five soils, a more extensive sampling encompassing diverse soil textures and densities is necessary for a comprehensive understanding of X-ray penetration behavior across various soil types.

Hydrogen resistance of reduced graphene oxide coatings prepared by electrophoretic deposition on duplex stainless steel

In this study, reduced graphene oxide (rGO) coatings were fabricated on duplex stainless steel (DSS) substrates using the electrophoretic deposition (EPD) method to evaluate their hydrogen resistance performance. The successful fabrication of rGO coatings was confirmed using Fourier Transform Infrared Spectroscopy (FT-IR) and X-ray Photoelectron Spectroscopy (XPS). The structural characteristics were characterized using Raman spectroscopy and X-ray Diffraction (XRD). The results indicate that the EPD voltage is a crucial factor affecting the surface quality of and hydrogen resistance performance of rGO. Lower voltages resulted in lower degrees of rGO reduction and higher surface wrinkle density, while higher voltages caused bubble formation, significantly degrading the coating quality and hydrogen resistance performance. The optimal hydrogen resistance was achieved at an EPD voltage of 7.5V and a deposition time of 6 minutes. Electrochemical hydrogen charging tests and thermal desorption analysis (TDA) demonstrated that rGO coatings prepared under optimal conditions exhibited excellent hydrogen resistance efficiency, significantly reducing hydrogen atom penetration in hydrogen environments. The study further revealed that bubble formation significantly reduces the hydrogen resistance of rGO, which is attributed to increased interlayer spacing and the loss of the “labyrinth effect”.

Optimizing beet seed germination via dielectric barrier discharge plasma parameters

This study explores the synergistic effects of gas composition and electric field modulation on beetroot seed germination using dielectric barrier discharge (DBD) plasma. The investigation initially focuses on the impact of air plasma exposure on germination parameters, varying both voltage and treatment duration. Subsequently, the study examines how different gas compositions (argon, nitrogen, oxygen, and carbon dioxide) affect germination outcomes under optimal air plasma conditions. Results indicate that plasma treatment significantly enhances germination rates and seedling growth relative to untreated controls. Notably, plasma exposure alters seed surface morphology and chemistry, increasing roughness, porosity, and hydrophilicity due to the formation of new polar functional groups. The highest germination rate (a 54.84 % increase) and germination index (a 40.11 % increase) were observed at the lowest voltage and shortest duration, whereas higher voltages and prolonged exposure reduced germination, likely due to oxidative stress. Among the tested gas environments, air plasma was most effective in enhancing water uptake and electrical conductivity, while oxygen plasma resulted in the highest germination index and marked improvements in root and shoot length. Conversely, carbon dioxide plasma treatment exhibited inhibitory effects on both germination and subsequent growth metrics. The results highlight the potential of DBD plasma technology to enhance agricultural productivity by optimizing seed germination and early growth. The study emphasizes the importance of precise parameter tuning, particularly gas composition and plasma exposure conditions, to maximize benefits while minimizing adverse effects, offering a refined approach to seed priming in agricultural practices.

Analysis of the effect of a spring constant of 980 N/m on a wave energy converter device due to heaving

Indonesia is a country with a larger sea area compared to its land area. Therefore, utilizing ocean current or wave energy as a renewable energy source, specifically for generating electricity through Wave Energy Converters (WEC), is a suitable solution. Wave Energy Converters (WEC) work on the basic principle of converting wave energy into linear motion or rotation to drive a generator and then convert it into electricity. The rotation is generated by the up-and-down movement of the pontoon affected by the pontoon's spring constant, which originates from sea waves. Hence, this study aims to analyze the effect of the spring constant on the pontoon due to heaving motion in response to sea waves. The study uses a spring constant of 980 N/m and is conducted with and without a planetary gear system. The highest voltage and current were achieved at a wave height of 0.35 m, producing a voltage of 84.5 V with a current of 8.26 A and a power of 698 Watts for the generator with the planetary system. For the generator without the planetary system, it produced a voltage of 1.73 V with a current of 0.046 A and a power of 0.0795 Watts with a gearbox shaft rotation of 37.32 RPM. The lowest voltage and current were observed at a wave height of 0.15 m, producing a voltage of 39.6 V with a current of 3.58 A and a power of 141.8 Watts for the generator with the planetary system. For the generator without the planetary system, it produced a voltage of 0.53 V with a current of 0.021 A and a power of 0.0111 Watts with a gearbox shaft rotation of 21.62 RPM

The Sharing Energy Storage Mechanism for Demand Side Energy Communities

Energy storage (ES) units are vital for the reliable and economical operation of the power system with a high penetration of renewable distributed generators (DGs). Due to ES’s high investment costs and long payback period, energy management with shared ESs becomes a suitable choice for the demand side. This work investigates the sharing mechanism of ES units for low-voltage (LV) energy prosumer (EP) communities, in which energy interactions of multiple styles among the EPs are enabled, and the aggregated ES dispatch center (AESDC) is established as a special energy service provider to facilitate the scheduling and marketing mechanism. A shared ES operation framework considering multiple EP communities is established, in which both the energy scheduling and cost allocation methods are studied. Then a shared ES model and energy marketing scheme for multiple communities based on the leader–follower game is proposed. The Karush–Kuhn–Tucker (KKT) condition is used to transform the double-layer model into a single-layer model, and then the large M method and PSO-HS algorithm are used to solve it, which improves convergence features in both speed and performance. On this basis, a cost allocation strategy based on the Owen value method is proposed to resolve the issues of benefit distribution fairness and user privacy under current situations. A case study simulation is carried out, and the results show that, with the ES scheduling strategy shared by multiple renewable communities in the leader–follower game, the energy cost is reduced significantly, and all communities acquire benefits from shared ES operators and aggregated ES dispatch centers, which verifies the advantageous and economical features of the proposed framework and strategy. With the cost allocation strategy based on the Owen value method, the distribution results are rational and equitable both for the groups and individuals among the multiple EP communities. Comparing it with other algorithms, the presented PSO-HS algorithm demonstrates better features in computing speed and convergence. Therefore, the proposed mechanism can be implemented in multiple scenarios on the demand side.

The Interfacial Ni/Fe─O─Y Bonds Contribute to High-Efficiency Water Splitting.

Developing economical and efficient electrocatalysts is critical for hydrogen energy industrialization through water electrolysis. Herein, a novel dual-site synergistic NiFe/Y2O3 hybrid with abundant interfacial Ni/Fe─O─Y bonds is designed by density functional theory (DFT) simulations. In situ Raman spectra combined with DFT calculations reveal that the interfacial Ni/Fe─O─Y units greatly promote H2O dissociation and optimize the adsorption of both H* and oxygen species, achieving excellent activity and durability for hydrogen evolution reaction. As expected, NiFe/Y2O3 exhibits a low overpotential of 27 mV at 10 mA cm-2 and robust stability of over 200 h at 1000 mA cm-2, and also outstanding water splitting performance with a low cell voltage of 1.64 V at 100 mA cm-2, showing significant potential for real-world applications.

A Novel Fast Contact Operating Mechanism of the Medium and Low Voltage Hybrid DC Current Limiting Circuit Breaker

In order to solve the problem of the slow initial speed caused by the large mass of the bistable permanent magnetic actuator (PMA) in the traditional bistable permanent magnetic–electromagnetic repulsion mechanism (PM-ERM), a novel fast contact operating mechanism is proposed by using the flexible spring system (SS) between the PMA and the ERM. The novel structure can separate the mass of the PMA and the ERM at the initial phase of the interrupting process, improve the initial speed of the contact and increase the initial opening distance of the contact. Firstly, the paper conducts an extensive investigation and analysis of the principle of the existing fast operating mechanism and points out the advantages and disadvantages of the existing mechanism. In order to meet the requirement of fast interrupting and improve the service life of the mechanism, a novel mechanism is proposed. And then, the working principle of the novel mechanism is introduced. The cooperative relationship between the ERM and the PMA and the working principle and performance parameter requirements of the ERM, SS and PMA are analyzed and designed. Finally, the feasibility of the novel mechanism is verified by the experiment. The results show that the opening distance of the novel operating mechanism can reach 2.25 mm in 1 ms. Compared with 1.24 mm of the traditional operating mechanism, it improves the initial opening distance of the contact by 81.5% and is conducive to the rapid interruption of the Hybrid DC current-limiting circuit breaker (HDCCLCB).

ИЗМЕРЕНИЕ СОПРОТИВЛЕНИЯ ЛАКОКРАСОЧНОГО ПОКРЫТИЯ В ЭЛЕКТРОЛИТЕ

The use of known methods for measuring the electrical resistance of a protective coating in an electrolyte is associated with the danger of using high voltage, which accelerates degradation of the coating. The structural diagram of a measuring device operating at a low voltage of up to 1.5 V is substantiated. The device contains two galvanic cells with an electrolyte, a capacitor, a switch, a digital multimeter, and a three-position switch. One galvanic cell is attached to the coating on a carbon steel plate and is equipped with an electrode made of stainless steel. The second galvanic cell is equipped with electrodes made of carbon and stainless steel. It is a source of reference voltage. The input resistance of the multimeter from 1 MOhm serves as a reference resistance. The maximum value of the measured coating resistance reaches 1400 MOhm. A formula is obtained for calculating the specific electrical resistance of the paint and varnish coating in an electrolyte solution. Using the manufactured device, the dynamics of changes in the specific electrical resistance of two coatings made of Raptor polyurethane paint with a hardener are studied. The coatings were applied in two and three layers, the duration of testing in the borofoska solution was 200 days. Upon completion of the tests, the specific electrical resistance of the three-layer coating decreased from 480 to 20 MOhm∙m, it was 4 times greater than the two-layer coating. This result indicates a significant increase in the protective resistance of the polyurethane coating after applying the third layer.

Under Voltage Relay System for Battery and DC Load Safety Using Arduino Nano

The quality of the electric power supply in an electrical system is very necessary. One of the important things that need to be considered is the quality of the voltage supply. The disturbance in the electrical system is under voltage. Undervoltage is an electrical system disturbance that will affect the performance of connected electrical equipment and reduce the life of the equipment, including battery components in DC voltage source electrical systems such as solar power plants. To anticipate this occurrence, Under Voltage Relay equipment is needed which can be used to protect batteries and DC equipment from under voltage conditions by using a potentiometer as a voltage divider and IC 7809 to reduce the voltage from the battery input, Relays to disconnect the load, LCD for monitoring and using Arduino Nano microcontroller control. The method used is a development method or Research and Development. This method is used as a basis for designing and manufacturing Low Voltage Relay devices to protect batteries and DC equipment. From the results of the tests carried out, it can disconnect the DC load when detecting low voltage conditions with an accuracy of ± 99.795%. for the normalized execution test for under voltage relay at voltages of 12 V and 24 V, there is a difference value of ± 0.096V and an error of ± 0.554%.

Design and performance investigation of tunnel-FET based energy efficient approximate and accurate adders targeted towards low power IoT nodes

Abstract The proliferation of IoT enabled SoCs in state-of-the-art consumer electronics has necessitated the use of beyond CMOS devices for the energy efficient computations and sensing design space. In the low supply voltage (VDD) regime, Tunnel FETs (TFETs) have shown serious potential at VDD less than 0.5 V. However, the inherent structure, characteristic interband tunneling and enhance Miller capacitance in TFETs do not allow the conventional CMOS logic design styles to be universally used for TFET based logic circuits. In this paper, we propose three energy efficient and novel TFET based accurate adder circuits namely, Static Energy Recovery Full adder (SERF), Complementary and Level Restoring Carry Logic Full adder (CLRCL) and Balanced Restoring Carry Logic full adder (BRCL) based on constituent TFET based functional units which do not use the CMOS design style. Further, novel approximate adders have been developed for energy efficient implementation in IoT nodes. The BRCL adder consumes approximately 60% less area and 85.36% and 89.6% less energy in comparison to SERF and CLRCL respectively. The approximate adders in the best and worst case facilitate approximately 92% and 75% savings in area and consumes 71% less power than the BRCL adder. When compared to the standard UMC 45 nm bulk MOSFET based designs, the TFET based accurate adders operate at 25% less energy while the approximate adders consume 40% less. All the circuit simulations have been performed using Spectre Simulator of Cadence and device characterization using 2D-TCAD tool.

Low Power Emission Pulse Generation Circuit Based on n-Type Amorphous In-Ga-Zn-Oxide Transistors for Active-Matrix Organic Light-Emitting Diode Displays

This paper presents a low power emission (EM) pulse generation circuit using n-type amorphous In-Ga-Zn-Oxide (a-IGZO) semiconductor thin-film transistors (TFTs). The low power consumption is achieved by avoiding the shoot-through current paths through an optimized inverter circuit. The proposed circuit consists of 12 TFTs and 2 capacitors including 6 TFTs and 1 capacitor for the inverter circuit to control the pulling-down TFTs. In addition, the wider variance range of the threshold voltage (Vth) from −4 V to 2.5 V is covered by additional 6 TFTs for series-connected two transistor (STT) schemes and two low supply voltages to take into account the negative Vth of depletion-mode TFTs. The simulation of 30 EM circuits is conducted over a 6.1-inch active-matrix organic light-emitting diode display of 120 Hz refresh rate and 3840 × 2160 (UHD) resolution. The power consumption of the EM circuit with the proposed inverter is measured at the low values from 0.836 mW to 0.568 mW over pulse widths from 3 to 2157 horizontal times. It is ensured that the proposed circuit achieves the low power consumption regardless of pulse widths.

Innovative Electrostatic Precipitator Solutions for Efficient Removal of Fine Particulate Matter: Enhancing Performance and Energy Efficiency

The removal of particulate matter (PM) from air streams is essential for advancing environmental technologies and safeguarding public health. This study explores the performance of an electrostatic precipitator (ESP) in eliminating fine and ultra-fine PM under varied experimental conditions. It uniquely examines the influence of PM size and feed rate on ESP removal efficiency. The system’s use of low voltages enhances energy sustainability, while its innovative design improves corona discharge, leading to significant reductions in fine and ultra-fine PM emissions. Plants using electrical devices are increasingly being incorporated into material processing lines to reduce pollution in the surrounding work area, as well as to collect particle emissions in the atmosphere. It is also possible to recycle some raw materials in this way with low energy consumption. This cleaning technology increases the added value of industrial equipment, which affects its competitiveness and its impact on sustainable manufacturing. The experimental results indicate a steady electrostatic field voltage of 15.1 kilovolts, with an airflow maintained at 0.8 m/s through a doser at 2.5 bar, eliminating the need for a fan. The PM feed rate varied between 2 and 20 mm/h, with six trials conducted to ensure the data were consistent. Preliminary studies devoid of ESP intervention demonstrated little PM removal, since buildup on the chamber walls distorted the results. The installation of the ESF markedly enhanced the removal efficiency, achieving up to 95.5%. Further analysis revealed that ESP performance depended on PM concentration in the agglomeration chamber, achieving a clearance rate exceeding 98% under optimal conditions. Fine PM (0.35 to 8.7 µm) was more efficiently removed than ultra-fine PM (0.2 to 0.35 µm). The highest removal efficiency was observed at a feed rate of 0.962 mg/s, while the lowest occurred at 0.385 mg/s. A strong positive correlation between particle concentration and removal efficiency (Pearson value up to 0.829) was observed, particularly at feed rates of 0.128, 0.641, and 1.283 mg/s. The study’s findings confirm that the ESP is highly effective in removing particulate matter, particularly fine and ultra-fine particles, with an optimal feed rate, significantly enhancing the system’s performance.

Study of A Heterojunction Double Gate Ferroelectric p-n-i-n Tunnel FET combining analytical modeling and TCAD simulation

A short channel Heterojunction Double Gate Ferroelectric p-n-i-n Tunnel Field Effect Transistor structure is proposed in this article to alleviate undesirable ambipolarity and Miller Capacitance and has a steeper subthreshold swing with improvement in ON state current compared to other conventional TFET structures. This work develops a physics based relevant analytical model of surface potential with the effect of gate fringing field and inclusive source and channel depletion region, drain current model, terminal charge and capacitance model to investigate its transient performance for the impact of ferroelectric polarization according to the Miller Ferroelectric polarization model. The proposed device is also validated using the SILVACO ATLAS device simulator, which yields a good agreement with the model, establishing its reliability and acceptability. The device achieves a steeper subthreshold of 31.3 mV/decade, an improved ON current∼5.9 x 10−4A/μmand enhanced transconductance∼0.105 ms as well as a very low energy delay product (EDP)∼4.07 x 10−3Js with hysteresis free operation at a low supply voltage∼0.5 V in a 40 nm technology node, making it desirable for ultra-low power analog and logic applications.

Research of Silicon and Zinc Oxide

As electronics develops, zinc becomes more and more useful and electronics producers consume more and more silicon because of it is abundant, it has a mature processing technology and it has a high carrier mobility. Those advantages made silicon perfect for integrated circuits. However, in some cases, silicon is no longer the best choice. Despite silicon’s advantages, there are problems for silicon. For example low breakdown voltage, low thermal conductivity and indirect band gap. Although silicon is still the most commonly used semiconductor, another type of semiconductor, zinc oxide starts to become more and more important in electronics. However, the two materials are used differently. This paper aims to provide the various properties of silicon and zinc oxide, and explain the reasons for their applications in electronics. The two materials are indispensable although they have a lot of disadvantages. Engineers must carefully consider the advantages and limitations of each material for specific applications to make optimal material selections.

Fully biodegradable electrochromic display for disposable patch

Flexible and biodegradable electronics have emerged as a promising solution for escalating electronic waste issue caused by the rapid development of skin patch electronics. Fully biodegradable displays are essential for visualizing biological/physical/chemical/electrochemical signals measured by a wide range of skin patch electronics. Here we propose fully biodegradable electrochromic display providing low operating voltage and low power consumption. The biodegradable transparent conductive electrode was fabricated by transferring free-standing tungsten nanomesh onto poly lactic-co-glycolic acid substrate using electrospinning templating, minimizing damage to the substrate. Electrochromic layer was tungsten oxide which is biodegradable, and a ferrocyanide/ferricyanide redox agent was utilized as a counter electrode reaction to enhance operational stability in an aqueous electrolyte by reducing operating voltage and side reactions. This display successfully visualized diverse signals from various biodegradable electronics such as UV sensors and electrochemical transistors, and finally underwent eco-friendly degradation in phosphate-buffered saline or soil under mild conditions.

Procedural findings and follow-up results of catheter ablation of atrial fibrillation in patients after radiation therapy for breast cancer

Abstract Backround Data on breast cancer radiation therapy (RT) associated atrial cardiomyopathy and its potential role in the pathophysiology of atrial fibrillation (AF) is very limited. Objectives To investigate the effect of breast cancer radiotherapy (RT) on atrial cardiomyopathy and its possible role in the pathophysiology of atrial fibrillation. What is the therapeutic success of antral pulmonary vein isolation (PVI) with possible substrate modifications (CFAE) in patients with breast cancer radiation therapy and paroxysmal or persistent atrial fibrillation. Methods We searched the institution’s data base for patients who received RT for breast cancer and underwent subsequently 3D mapping guided AF ablation. Intraprocedural mapping data and short- and long-term results of ablation were evaluated according to "no low voltage" and "low voltage" present. Low voltage amplitudes in bipolar electrograms were defined as <0.5 mV for endocardial maps created during SR and <0.3mV during AF. Ablation strategy comprised pulmonary vein isolation (PVI) ± additional substrate modification according to the mapping results. Follow Up (FU) was evaluated using repetitive 7-days Holter ECG and clinical visits. Results We included 45 patients (all female, 70.9±7.2 years) with paroxysmal or persistent AF (n=18 and n=27). In 3D mapping, 60% of the patients (27/45) showed left atrial low voltage (LV group) with the majority showing low voltage in the anterior wall of the left atrium (LA) in 18 of 45 patients (40%). PVI with ablation of complex fractionated signals (CFAE) was predominantly performed (18/27). After one ablation, 33.3% (9) of the patients in the LV group were recurrence-free and after an average of 1.9 ablations, freedom from recurrence was achieved in 21 patients with low voltage (77.8%). In 18 patients, no low voltage was detected (NLV group) and PVI only was performed in the majority (14/18). In this NLV group, 61.1% (11) of the patients were recurrence-free after one ablation and freedom from recurrence was achieved in 72.2% (13) after an average of 1.2 ablations. Conclusion Thoracic radiation therapy in patients with breast cancer can lead to low voltage in the LA with the predominant low voltage location being the anterior wall of the LA. An extended ablation strategy (PVI & CFAE) can show good treatment options in these patients with atrial fibrillation, with high freedom from recurrence after a mean of two ablation procedures.Freedom from recurrence after ablationCharacteristics of left atrium (LA)

Prognostic value of baseline and follow-up ECG in patients with biopsy-proven fulminant myocarditis

Abstract Background Fulminant myocarditis represents a life-threatening condition with poor outcomes characterized by increased short- and long-term mortality and need for heart transplant. Treatment largely relies on mechanical support and immunosuppressive therapy guided by histologic and virology findings but reliable short-term prognostic markers guiding therapy and management are still lacking. We hypothesised that baseline and short-term ECG evolution may provide relevant easily accessible prognostic information in these patients. Purpose We sought to assess the prognostic value of baseline and short-term follow-up ECG in patients affected by fulminant myocarditis. Methods We retrospectively enrolled patients with biopsy-proven fulminant myocarditis according to current diagnostic criteria. We evaluated baseline and follow-up ECG (performed 3 to 7 days after admission) together with clinical, laboratory and histologic data. The primary endpoint was a composite of in-hospital mortality or need for urgent heart transplantation. Results We enrolled 39 patients (22/39 M, 56.4%) and a mean age of 38 years. Histology demonstrated lymphocytic myocarditis in 35/39 cases, 2 eosinophilic and 1 giant cell myocarditis, 1 sarcoidosis. All patients received vasopressor and/or inotrope therapy with 19/39 requiring mechanical circulatory support. Follow-up ECGs were performed after 4.8±1.3 days from admission. The primary endpoint was reached in 7/39 patients (17.9%) with 5 deaths and 2 urgent cardiac transplants. These patients more commonly required mechanical (85.7% vs 40.6%, p=0.044) or extracorporeal membrane oxygenator (85.7% vs 12.5%, p<0.001) support and showed higher lactate levels on admission (11.0±7.3 vs 4.2±3.1 mmol/L, p=0.001). They also more frequently had cardiac arrest as first clinical presentation (50. 0% vs 9.7%, p=0.022) and sustained ventricular tachycardia (71.4% vs 15.6%, p=0.007) in the acute phase. Patients with a worse outcome showed persistence of low voltages (< 5 mm in all peripheral leads) at follow-up ECG (100.0% vs 37.5%, p=0.003) with lower R wave amplitude in lead II (1.1±0.9 vs 4.0±2.6 mm, p=0.004), III (0.7±0.5 vs 2.5±2.2 mm, p=0.043), aVF (0.9±0.7 vs 3.0±2.0 mm, p=0.01) and V6 (3.0±2.8 vs 7.5±4.2 mm, p=0.011) and reduced S wave amplitude in V1 (2.6±3.9 vs 6.4±4.4 mm, p=0.047), V2 (3.9±3.9 vs 10.2±6.7 mm, p=0.035), V3 (3.3±3.2 vs 10.7±6.7 mm, p=0.007) leads. Low QRS voltages at baseline ECG were not associated with worse prognosis (71.4% vs 46.9%, p=0.407). No significant difference in terms of steroid (85.7% vs 78.1%, p=0.929) or other immunosuppressive (14.3% vs 31.2%, p=0.366) therapy was observed between the groups. Conclusions In patients with fulminant myocarditis, persistence of low QRS voltages at 5-day follow-up ECG is associated with adverse in-hospital outcomes. Short-term ECG evolution can identify high-risk patients requiring earlier and more intensive mechanical and pharmacological treatment.

Clinical and genetic profiles of patients with hereditary and wild type transthyretin amyloidosis: the transthyretin cardiac amyloidosis registry in the state of Sao Paulo, Brazil REACT-SP

Abstract Introduction Transthyretin amyloidosis (ATTR) is a multisystem disease caused by the deposition of fibrillar protein in organs and tissues. ATTR genotypes and phenotypes are highly heterogeneous. Purpose We designed the Transthyretin Cardiac Amyloidosis Registry in the state of São Paulo (REACT-SP), aiming to describe the demographic, genetic, clinical, and diagnostic test results and treatment of patients with ATTR. Methods We present data on physical signs and symptoms, cardiac and neurological assessments, and genetics in patients enrolled in the Transthyretin Cardiac Amyloidosis Registry in the state of São Paulo, Brazil. Results Six hundred-forty-four patients were enrolled, 505 with the variant form (ATTRv) and 139 with wild-type (ATTRwt). Sixteen different mutations were detected, the most common being Val50Met (48.3%) and V142Ile (40.8%). Overall, more than half of the patients presented cardiological involvement, and the difference in this proportion between the ATTRv and ATTRwt groups was significant (43.9 vs. 89.9%; p<0.001). The neurological phenotype also differed between ATTRv and ATTRwt (56.8 vs. 31.7%; p<0.001). The mixed phenotype was found in 25.6% of the population, without a significant difference between the forms of amyloidosis. A group of patients remained asymptomatic (10.4%), with a lower proportion of asymptomatic ATTRwt patients. The median time between the onset of symptoms and diagnosis was 1,853 (IQR 1277–2997) days, which was longer in ATTRv patients than in ATTRwt patients (p<0.001). Sinus rhythm was reported in 74.2%, atrial fibrillation in 17.0%, low voltage in 28.6%, repolarization abnormalities in 39.8%, and pseudo infarction in 27.4%. Echocardiography showed median Left Ventricular Ejection Fraction (LVEF) was 60%, Interventricular Septum (IVS) 14 mm, Posterior Wall Thickness (PWT) 13 mm, Left Atrium (LA) 41 mm, Left Ventricular Diastolic Diameter (LVDD) 45 mm, Left Ventricular Systolic Diameter (LVSD) 30 mm, basal Right Ventricular Diastolic Diameter (RVDD) 35 mm and Left Ventricle (LV) longitudinal strain 9.1%. There was some degree of LV diastolic dysfunction in 38.4%, apical sparing in 31.3%, and thrombus or masses in 1.0%. Late Gadolinium Enhancement (LGE) was absent in 29% and was subendocardial in 35.5%, transmural in 13.7%, mesocardial in 13.7%, and epicardial in 8.2%. Conclusions This study details the clinical and genetic spectrum of patients with ATTR in São Paulo, Brazil. This preliminary analysis highlights the considerable phenotypic heterogeneity of neurological and cardiac manifestations in patients with variant and wild-type ATTR.

The spectrum of ECG abnormalities in a large cohort of histologically proven cardiac tumors

Abstract Background Cardiac tumors represent a heterogeneous clinical scenario. The role of ECG in the diagnostic work-up remains to be investigated. Objectives To describe the spectrum of electrocardiographic abnormalities in a large cohort of histologically proven cardiac tumors and to evaluate potential red flags of malignancy. Material and Methods 247 consecutive patients with histologically proven cardiac tumors and available ECG at Bologna University Hospital were enrolled. All ECGs were independently analyzed off-line using a manual caliper by two experienced cardiologists who were blinded to clinical information and histological results. In case of disagreements, a third consensus re-assessment was performed to resolve any discrepancies. Multivariable regression analysis was used to assess potential predictors of malignancy among electrocardiographic abnormalities. Results Of 247 patients, 98 (39.7%) had malignant tumors. Compared with patients with benign tumors, those with malignant tumors exhibited a higher heart rate, right axis deviation, greater depolarization, repolarization abnormalities and bradyarrhythmia at presentation. Regarding specific ECG features, a higher heart rate on admission (p=0.001), bradyarrhythmias (p=0.01), ischemic-like repolarization abnormalities (ST-segment deviation, both depression and elevation, and negative T-wave; p<0.001) and low voltages (p=0.005) were identified as independent predictors of malignancy. Conclusion ECG is frequently abnormal in case of malignant cardiac tumors. Some specific electrocardiographic changes could have a supportive role in the diagnostic workup of patients with cardiac tumors by increasing the clinical suspicion of malignancy.ECG Tumors