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The relationship between height and incident atrial fibrillation (AF) has recently been demonstrated. We aimed to evaluate the impact of height on outcomes of ablation in patients with drug-refractory symptomatic paroxysmal AF (PAF). A total of 689 patients (470 males; age, 53.0 ± 11.7 years) with symptomatic paroxysmal AF receiving index catheter ablation (CA) between 2003 and 2013 were enrolled in this study. The baseline characteristics, ablation, and follow-up results were evaluated. The patients were categorized according to the quartiles of height for each sex. Patients in the lower quartiles of height had a lower incidence of AF recurrence (log-rank p = 0.022). Height in female patients was strongly associated with AF recurrence (p = 0.027) after an index ablation in the 6.33 ± 4.32 years of follow-up. Female patients > 159 cm in height had a higher likelihood of AF recurrence after index CA (HR = 2.01, 95% CI: 1.24–3.25, p = 0.005) than that in those below this height. In computed tomography (CT) scan, the superoinferior diameter of the left atrium (LA) correlated with body height in females, but not in male patients. Height is associated with AF recurrence after the index CA of PAF in female patients. In Asian populations, women above height 159 cm are twice as likely to have AF recurrence post-ablation as shorter women.

INTRODUCTION Accurate identification of slow conducting regions in patients with scar-related atrial tachycardia (AT) is difficult using conventional electrogram annotation for cardiac electroanatomic mapping (EAM). Estimating delays between neighboring mapping sites is a potential option for activation map computation. We describe our initial experience with CARTO 3 Coherent Mapping (Biosense Webster Inc,) in the ablation of complex ATs. METHODS Twenty patients (58 ± 10 y/o, 15 males) with complex ATs were included. We created three-dimensional EAMs using CARTO 3 system with CONFIDENSE and a high-resolution mapping catheter (Biosense Webster Inc). Local activation time and coherent maps were used to aid in the identification of conduction isthmus (CI) and focal origin sites. System-defined slow or nonconducting zones and CI, defined by concealed entrainment (postpacing interval

The relationship between height and incident atrial fibrillation (AF) has recently been demonstrated. We aimed to evaluate the impact of height on outcomes of ablation in patients with drug-refractory symptomatic paroxysmal AF (PAF).A total of 689 patients (470 males; age, 53.0 ± 11.7 years) with symptomatic paroxysmal AF receiving index catheter ablation (CA) between 2003 and 2013 were enrolled in this study. The baseline characteristics, ablation, and follow-up results were evaluated. The patients were categorized according to the quartiles of height for each sex.Patients in the lower quartiles of height had a lower incidence of AF recurrence (log-rank p = 0.022). Height in female patients was strongly associated with AF recurrence (p = 0.027) after an index ablation in the 6.33 ± 4.32 years of follow-up. Female patients 159 cm in height had a higher likelihood of AF recurrence after index CA (HR = 2.01, 95% CI: 1.24-3.25, p = 0.005) than that in those below this height. In computed tomography (CT) scan, the superoinferior diameter of the left atrium (LA) correlated with body height in females, but not in male patients.Height is associated with AF recurrence after the index CA of PAF in female patients. In Asian populations, women above height 159 cm are twice as likely to have AF recurrence post-ablation as shorter women.

Signal-averaged electrocardiogram (SAECG) provides not only diagnostic information but also the prognostic implication of ablation in arrhythmogenic right ventricular cardiomyopathy (ARVC).This study aimed to validate the role of SAECG in identifying arrhythmogenic substrates requiring an epicardial approach in ARVC.Ninety-one patients with a definite diagnosis of ARVC who underwent successful ablation for drug-refractory ventricular arrhythmia were enrolled and classified into 2 groups: group 1 who underwent successful ablation at the endocardium only and group 2 who underwent successful ablation requiring an additional epicardial approach. The baseline characteristics of patients and SAECG parameters were obtained for analysis.Male predominance, worse right ventricular (RV) function, higher incidence of syncope, and depolarization abnormality were observed in group 2. Moreover, the number of abnormal SAECG criteria was higher in group 2 than in group 1. After a multivariate analysis, the independent predictors of the requirement of epicardial ablation included the number of abnormal SAECG criteria (odds ratio 2.8, 95% confidence interval 1.4-5.4; P = .003) and presence of syncope (odds ratio 11.7; 95% confidence interval 2.7-50.4; P = .001). In addition, ≥2 abnormal SAECG criteria were associated with larger RV endocardial unipolar low-voltage zone (P.001), larger RV endocardial/epicardial bipolar low-voltage zone/scar (P.05), and longer RV endocardial/epicardial total activation time (P.001 and P = .004, respectively).The number of abnormal SAECG criteria was correlated with the extent of diseased epicardial substrates and could be a potential surrogate marker for predicting the requirement of epicardial ablation in patients with ARVC.

Coronary artery disease combined sepsis associated myocardial ischemia resulting in diffuse ST elevation on electrocardiogram has rarely been reported. We reported a rare case of diffuse ST elevation precipitated by septic shock and preexisting severe atherosclerosis heart disease. In clinical scenario, it is imperative for physicians to be aware of non-ischemic ST elevation etiologies and avoid inappropriate activation of the percutaneous coronary intervention (PCI) protocol, while not missing ST elevation myocardial infarction.

This study concerns the use of conductive carbon material with different content and structure to produce carbon fiber paper for use in proton exchange membrane fuel cells, and investigates how changes in the content and structure of the conductive carbon material influence fuel cell performance. In this study, phenolic resin is used as a conductive carbon material, and is subjected to heat treatment at temperatures of 700 °C, 1000 °C, and 1400 °C, which changes its structure. Before carbon fiber paper is prepared from carbon felt, the felt is treated with phenolic resin solutions with resin content of 5, 10, 15, 20, 25, and 30 wt%. During fuel cell testing, torsion of 40, 60, 80, 100, and 120 kgf-cm is applied. The study found that when the phenolic resin content is 15 wt%, the heat treatment temperature 1400 °C, the test area 25 cm 2 , and the test temperature 65 °C, a fuel cell can achieve a current density of 2020 mA cm −2 at 0.5 V and torque of 120 kgf-cm.

The negative electrode of a lithium-ion battery should have the characteristics of large charge capacity, excellent charge and discharge cycle, steady discharge voltage, low irreversible charge capacity, and stable electrolyte. Natural graphite and mesocarbon microbeads (MCMB) are the most common materials used for the negative electrodes of such batteries. This study examines the effect of the use of homemade non-modified MCMB (HMM), modified MCMB (HMMQ), and natural graphite (NG) to produce electrodes on the batteries' high current charge–discharge behavior. In this experiment, the charge–discharge results showed that the voltage plateaus of HMM and HMMQ sloped due to short-range structural order, which enabled the intercalation and deintercalation of lithium ions to occur at different voltages. When HMMQ was charging and discharging high current at a rate of 2 C, the battery's charge capacity reached 160 mAh·g − 1 and the coulometric efficiency exceeded 96%. Following the start of charging and discharging, a stable solid electrolyte interface (SEI) layer formed on HMMQ. The charge capacity of HMMQ was approximately 167 mAh·g − 1 after 100 charge–discharge cycles at 1 C, and the cycles were stable. According to FTIR analysis, the content of the SEI layer produced within HMMQ consisted of Li 2 CO 3 and (CH 2 OCOLi) 2 , and was stable, non-soluble, and passive. Negative electrodes made using modified material displayed good stability throughout many cycles when charging and discharging at a high current.

Rationale Esophageal chest pain is difficult to be identified, and the diagnosis requires a high index of clinical suspicion. Upon presentation, they are difficult to be differentiated from acute coronary syndrome (ACS) by symptomatology alone. Patient concerns We report a 71-year-old woman with multiple risk factors for coronary heart disease who presented with acute central spastic chest pain and was diagnosed as ACS in emergency department. Diagnoses Chest computed tomography revealed 1 radiopaque lesion over the upper-third of the esophagus. One fishbone with 3-pointed heads stuck in the esophagus was noted under esophagogastroscopic examination. Interventions The fishbone was extracted successfully via endoscopy under general anesthesia. Outcomes The woman was discharged uneventfully after 3 days' hospitalization. Lessons This case illustrates that, even in emergency, clinicians should always keep in mind the possibility of esophageal foreign body impaction when confronted with frank central chest pain without associated gastrointestinal symptoms. This holds true even in the scenario of multiple cardiovascular risk factors and absence of ingestion history.

This study discusses the relationship between performance and carbon fiber diameter (400 nm–1 μm) in fuel cells employing carbon fiber paper produced from PAN fiber felt, and also examines the effect of carbon fiber paper thickness, air permeability, porosity, and surface resistivity on performance. The researchers fabricate gas diffusion layers (GDLs) with a small carbon fiber diameter from PAN fiber employing the two processes of stabilization and carbonization, and investigate the relationship between fiber diameter and air permeability in the gas diffusion layer material. Carbon fiber paper made in this study is left as is or impregnated with 10 wt% phenolic resin or FEP. When the tested area is 25 cm2, the test temperature 40 °C, and the carbon fiber paper impregnated with 10 wt% phenolic resin, the paper has a fiber diameter of 1 μm and an air permeability is 29 cm3 cm−2 s−1, and a test fuel cell yields 997 mA cm−2 at a load of 0.5 V. Carbon fiber paper impregnated with 10 wt% FEP has a smaller carbon fiber diameter of 400 nm and an air permeability of only 1 cm3 cm−2 s−1; a test fuel cell made with this material yields 683 mA cm−2 at a load of 0.5 V.

This study uses fuel cell gas diffusion layers (GDLs) fabricated in the laboratory from carbon fiber cloth with different concentrations of hydrophobic agents in proton exchange membrane fuel cells (PEMFCs), and investigates the relationship between the hydrophobic agent content of the carbon fiber cloth and fuel cell performance. The paper examines the effect of hydrophobic agent content on GDL thickness, contact angle, air permeability, and surface and through-plane resistivity. Carbon fiber cloth is impregnated with hydrophobic agent concentrations of 0, 3, 5, 10, 30, and 50 wt%, and the resulting GDLs are subjected to performance tests. When the test piece area is 25 cm 2 , the test temperature 80 °C, the gasket thickness 0.36 mm, and the hydrophobic agent content 5 wt%, a fuel cell using the GDL has a current density of 1430 mA cm −2 at 0.3 V.

This study uses fuel cell gas diffusion layers (GDLs) fabricated in the laboratory from carbon fiber cloth with different structure in proton exchange membrane fuel cells (PEMFCs), and investigates the relationship between the structure of the carbon fiber cloth and fuel cell performance.The paper discusses the relationship between fuel cell performance and structure of the carbon fiber cloth, and also examines the effect of the carbon fiber cloth’s thickness, air permeability, surface resistivity, XRD and elemental analysis. Carbon fiber cloth is carbonized at rates of 190, 220, 250, 280, and 310 °C min −1 respectively, and the resulting carbon fiber cloth is tested in cells. When the test piece area is 25 cm 2 , the test temperature 40 °C, the gasket thickness 0.36 mm, and the carbonization rate 280 °C min −1 , a fuel cell using the carbon fiber cloth achieves a current density of 1968 mA cm −2 and a maximum power density of 633 mW cm −2 at 0.3 V.

This study uses different carbon fiber reinforcing materials impregnated with different phenolic resin concentrations to produce composite materials for use as fuel cell gas diffusion layer (GDL) s...

Thanks to its excellent conductivity, gas permeability, and corrosion resistance, carbon fiber cloth is widely used in many applications. The carbon electrodes used in polymer electrolyte membrane fuel cells consist of gas diffusion and catalyst layers. While most gas diffusion layers are made from carbon fiber paper or carbon fiber cloth, the use of conventional carbon fiber cloth to produce fuel cell electrodes may result in peeling fibers and material that is excessively soft and difficult to assemble. This study employs PAN-based carbon fiber cloth and uses phenolic resin to improve the structure and characteristics of the gas diffusion layer (GDL). This study focused on the material used in the GDL. Results indicate that an improved carbon fiber cloth can eliminate assembly difficulties. Investigation of the effect of different resin contents revealed that GDL carbon fiber cloth with a relatively low resin content exhibits good through-plane resistance and thus offers good cell performance.

This study employed fuel cell gas diffusion layers (GDLs) consisting of carbon fiber paper made from carbon fiber felt with different yard weights in proton exchange membrane fuel cells (PEMFCs), and investigated the relationship between the yard weight of the carbon fiber paper and the fuel cell performance and thickness of the gasket. In this paper we discuss the relationship between carbon fiber felt with different yard weights and fuel cell performance and also explore the effect of carbon fiber paper thickness, air permeability, surface resistivity, and structural study. We focused on the material used for the gas diffusion layer in this study. Carbon fiber paper made in-house in this study contained 10 wt% (all percentages are by weight unless otherwise noted) phenolic resin. When the tested area was 25 cm 2 , the test temperature was 40 °C, the gasket thickness was 0.06 mm, and the yard weight 70 g m −2 , fuel cell current density was 1968 mA cm −2 at a load 0.3 V. When the gasket thickness was 0.36 mm and yard weight was 190 g m −2 , fuel current density was 1710 mA cm −2 at a load of 0.3 V.

This study uses fuel cell gas diffusion layers (GDLs) made from carbon fiber paper containing carbon black in proton exchange membrane fuel cells (PEMFCs) in order to determine the relationship between carbon black content and fuel cell performance. The connection between fuel cell performance and the carbon black content of the carbon fiber paper is discussed, and the effects of carbon black on the carbon fiber paper's thickness, density, and surface resistivity are investigated. When a carbon fiber paper GDL contains 10 wt% phenolic resin and 2% carbon black, and reaction area was 25 cm2 and operating temperature 40 °C, tests show that a carbon electrode fuel cell could achieve 1026.4 mA cm−2 and maximum power of 612.8 mW cm−2 under a 0.5 V load.

The gas diffusion layer (GDL) in a proton exchange membrane fuel cell (PEMFC) is one of the functional components that provide a support structure for gas and water transport. The GDL plays a crucial role when the oxidant is air, especially when the fuel cell operates in the higher current density region. There has been an exponential growth in research and development because the PEMFC has the potential to become the future energy source for automotive applications. In order to serve in this capacity, the GDL requires due innovative analysis and characterization toward performance and durability. It is possible to achieve the optimum fuel cell performance only by understanding the characteristics of GDLs such as structure, pore size, porosity, gas permeability, wettability, thermal and electrical conductivities, surface morphology and water management. This review attempts to bring together the characterization techniques for the essential properties of the GDLs as handy tools for R&D institutions. Topics are categorized based on the ex-situ and in-situ characterization techniques of GDLs along with related modeling and simulation. Recently reported techniques used for accelerated durability evaluation of the GDLs are also consolidated within the ex-situ and in-situ methods.

Proton exchange membrane fuel cells (PEMFCs) have been widely studied and discussed in the field of energy owing to their high energy efficiency and low waste emissions. A PEMFC uses hydrogen gas as a fuel, and works by causing hydrogen ions to link up with oxygen, producing liquid water as its sole by-product. The design of a PEMFC's micro-porous layer (MPL) can not only enhance cell performance, but also achieve better water management in a PEMFC system. In this paper, we examine the effects of spray and scrape MPL preparation methods on PEMFC performance. Our experimental results indicated that application of an MPL using the spray method yields better fuel cell performance. Furthermore, scanning electron microscopy (SEM) images reveal that the spray method produces pores with smoother surfaces and achieves a more uniform pore distribution. When the carbon black composition was 3 wt%, the current density of cells with MPL produced using the spray method reached 1210 mAcm –2 at a cell voltage of 0.5 V.

Gas diffusion layers (GDL) in proton exchange membrane fuel cells were prepared by graphitization of polyacrylonitrile carbon fiber cloths, to enhance their properties, such as, electrical conductivity, which was examined by electrical tests, X-ray diffraction, and elemental analysis. The results indicated that electrical resistivity declined, L(subscript c) increased, and d002 decreased with an increase in the heat-treatment temperature. Carbon fiber cloths with a higher heat-treatment temperature performed better as GDLs in terms of current density and power density.