Isolated Hyperacute T-Waves in West Nile Encephalitis Indicating Atypical Variant of Stress-Induced Cardiomyopathy

Several cardiac outcomes have been reported with West Nile-encephalitis;however, the underlying pathophysiology remains complex. We present a 42-year-old female, with multiple sclerosis, whose neurological symptoms and respiratory decline were finally explained by the diagnosis of West Nile-encephalitis. During her admission, the isolated peaked T-waves indicated the underlying stress-induced cardiomyopathy. The absence of all other causes of hyperacute T-waves, their subsequent resolution with the resolution of infection and improvement in wall motion abnormalities, further supported the association. This case highlights the importance of considering hyperacute T-waves in an approach towards the diagnosis of WNV-encephalitis related atypical variant of stress-induced cardiomyopathy.

T/R双模微波功率模块技术及其应用

微波功率模块(MPM)是真空电子器件和固态电子器件组合而成的一种新型微波功率器件,具有频率高、频带宽、功率大、体积重量小等特点,它使常规行波管的应用变得更加便利和广泛。现代战争向雷达、电子战综合一体化方向发展,这就要求功放既能工作在高峰值功率、低占空比的高模工作方式,也能工作在低峰值功率、准连续波的低模工作方式,针对这一需求,结合电子系统收发共孔径的要求,提出了T/R双模MPM技术。T/R双模MPM技术的核心是T/R双模行波管,基于三端口双向T/R行波管,通过在慢波系统的衰减器附近设置一个耦合口,实现行波管的信号反向接收功能;通过T/R双模行波管设计、双模放大均衡组件、双调制栅极电源等技术实现MPM的双模双向功能。T/R双模MPM应用前景广阔,特别是在基于无人机平台的作战应用中的具有明显优势。

MTWA技术联合血清miR-130a对心脏再同步化治疗后CHF患者室性心律失常的预测价值

目的探讨微伏级T波电交替(MTWA)技术联合血清微小RNA-130a(miR-130a)对心脏再同步化治疗(CRT)后慢性心力衰竭(CHF)患者室性心律失常的预测价值。方法前瞻性选取2021年3月至2022年1月郑州大学第一附属医院收治的130例经CRT治疗的CHF患者,均于CRT前、CRT 6个月后进行MTWA检查和血清miR-130a检测。所有患者均随访12个月,失访7例,根据随访期间是否发生室性心律失常分为发生组26例和未发生组97例,比较两组患者CRT前和CRT 6个月后的MTWA参数、血清miR-130a水平;采用Spearman相关系数法分析MTWA参数、血清miR-130a与CHF患者室性心律失常的相关性;采用受试者工作特征(ROC)曲线及曲线下面积(AUC)分析MTWA、血清miR-130a预测CHF患者室性心律失常的价值。结果CRT前、CRT 6个月后发生组V1导联MTWA_(max)、V1导联8:00 am MTWA、V5导联MTWA_(max)、V5导联8:00 am MTWA、miR-130a均高于未发生组,差异均有统计学意义(P<0.05);Spearman相关系数法分析结果显示,CRT前、CRT 6个月后V1导联MTWA_(max)、V1导联8:00 am MTWA、V5导联MTWA_(max)、V5导联8:00 am MTWA及miR-130a均与CHF患者室性心律失常发生呈正相关(P<0.05);ROC曲线分析结果显示,CRT前、CRT 6个月后V1导联MTWA_(max)、V1导联8:00 am MTWA、V5导联MTWA_(max)、V5导联8:00 am MTWA及血清miR-130a联合预测的AUC分别为0.912、0.933(P<0.05)。结论MTWA参数、血清miR-130a与CHF患者室性心律失常存在一定线性关系,CRT治疗前后MTWA参数和血清miR-130a联合预测CHF患者发生室性心律失常具有一定的价值。

MoS_(2)-Decorated/Integrated Carbon Fiber:Phase Engineering Well-Regulated Microwave Absorber

Phase engineering is an important strategy to modulate the electronic structure of molybdenum disulfide(MoS_(2)).MoS_(2)-based composites are usually used for the electromagnetic wave(EMW)absorber,but the effect of different phases on the EMW absorbing performance,such as 1T and 2H phase,is still not studied.In this work,micro-1T/2H MoS_(2) is achieved via a facile one-step hydrother-mal route,in which the 1T phase is induced by the intercalation of guest molecules and ions.The EMW absorption mechanism of single MoS_(2) is revealed by presenting a comparative study between 1T/2H MoS_(2) and 2H MoS_(2).As a result,1T/2H MoS_(2) with the matrix loading of 15%exhibits excellent microwave absorption property than 2H MoS_(2).Furthermore,taking the advantage of 1T/2H MoS_(2),a flexible EMW absorbers that ultrathin 1T/2H MoS_(2)grown on the carbon fiber also performs outstanding performance only with the matrix loading of 5%.This work offers necessary reference to improve microwave absorption performance by phase engineering and design a new type of flexible electromagnetic wave absorption material to apply for the portable microwave absorption electronic devices.

Seismic Wave Propagation and Excitation in Multi-layered Media with Irregular Interfaces Part (Ⅰ): SH Case

Study of seismic wave excitation and propagation in laterally heterogeneous media was an active and important subject in seismology in the past two decades, numerous analytical and numerical efforts have been made in this research field. In this article, I have, first, made a brief review on those developments and then introduced and summarized a unified and efficient method, global generalized reflection-transmission (abbreviated to R/T thereafter) matrices method, for synthetic seismograms in multi-layered media with irregular interfaces developed by the author [24~26]. As demonstrated in this article, this method could be regarded as an extension of the generalized R/T coefficients method for the horizontally layered case [2,5] to the layered media with irregularly shaped interfaces by incorporating the T matrices technique [27,28]. Because of the use of a recursive scheme in computing the global generalized R/T matrices, this method is efficient, particularly for the case with a large number of

T Wave Amplitude Deviation as a Participation Marker of Glycolysis in Myocardial Repolarization

Glucose metabolism is essential for heart physiology, especially in ischemic conditions. Anaerobic glycolysis participates along with aerobic fatty acid oxidation in generating energy supply, and the balance is shifted towards fatty acids. In the case of aerobic path restriction due to coronary artery disease (CAD), this ratio changes. The aim of the present research was to discover the aspects of glycolysis in cardiac electrophysiology.?We utilized the normalized (by average value) T wave amplitude deviation values, named the G criterion,?from high-resolution, 12-channel, 120-seconds-long electrocardiograms,?which were obtained using DACG technology. The calculated G criterion allows a quantitative assessment of the ischemic process and corresponds to the functional class (FC) according to the Canadian cardiovascular classification. We examined 22 healthy people and 79 proven CAD patients: 24 II FC, 40 III FC and 15 IV FC by original ECG and fasting blood sugar tests. A strong correlation was found between the average G criterion from all 12 channels and the level of fasting blood sugar (r = +0.88). In the control group, blood sugar levels were 91 ± 6.5 mg/dl, II FC 103 ± 14.8 mg/dl (p < 0.01), III FC 113 ± 23.4 mg/dl (p < 0.001), and IV FC 152 ± 42.4 (p < 0.001). Moreover, the correlation factor (average G criterion and blood sugar) was strong and positive in each group: control +0.72, II FC +0.83, III FC +0.76, and IV FC +0.89. For the first time, heart electrical activity from the ECG curve was associated with high glucose level as one of the main CAD risk factors. The presence of such dependence of increased blood sugar level from the severity of the ischemic process in the myocardium indicates that hyperglycemic reaction is adaptive and can accelerate the anaerobic glycolysis for energy demand compensation in heart muscle.

Predicting apical hypertrophic cardiomyopathy using T-wave inversion:Three case reports

BACKGROUND Apical hypertrophic cardiomyopathy(AHCM)is a subtype of hypertrophic cardiomyopathy.Due to its location,the thickening of the left ventricular apex can be missed on echocardiography.Giant negative T waves(GNTs)in left-sided chest leads are the hallmark electrocardiogram(ECG)change of AHCM.CASE SUMMARY The first patient was a 68-year-old woman complaining of recurrent chest tightness persisting for more than 3 years.The second was a 59-year-old man complaining of spasmodic chest tightness persisting for more than 2 years.The third was a 55-year-old woman complaining of recurrent chest pain persisting for 4 mo.In all three cases,GNTs were observed several years prior to apical cardiac hypertrophy after other causes of T-wave inversion were ruled out.CONCLUSION Electrophysiological abnormalities of AHCM appear earlier than structural abnormalities,confirming the early predictive value of ECG for AHCM.

Bayesian Rayleigh wave inversion with an unknown number of layers

Surface wave methods have received much attention due to their efficient, flexible and convenient characteristics. However, there are still critical issues regarding a key step in surface wave inversion. In most existing methods, the number of layers is assumed to be known prior to the process of inversion. However, improper assignment of this parameter leads to erroneous inversion results. A Bayesian nonparametric method for Rayleigh wave inversion is proposed herein to address this problem. In this method, each model class represents a particular number of layers with unknown S-wave velocity and thickness of each layer. As a result, determination of the number of layers is equivalent to selection of the most applicable model class. Regarding each model class, the optimization search of S-wave velocity and thickness of each layer is implemented by using a genetic algorithm. Then, each model class is assessed in view of its efficiency under the Bayesian framework and the most efficient class is selected. Simulated and actual examples verify that the proposed Bayesian nonparametric approach is reliable and efficient for Rayleigh wave inversion, especially for its capability to determine the number of layers.

Scattering of Tollmien-Schlichting waves as they pass over forward-/backward-facing steps

Forward-/backward-facing steps in boundary-layer flows are often seen in engineering applications, and they have potential impacts on laminar-turbulent transition through scattering of the oncoming instability modes(e.g., Tollmien-Schlichting(T-S) waves). This issue is studied in the present paper by applying a local scattering framework, which is a rather generic mathematical framework on describing the mode scattering process. In this framework, a high-Reynolds-number triple-deck formalism is employed, and a transmission coefficient, defined as the ratio of the asymptotic amplitude of the instability mode downstream of the step to that upstream, is introduced. Through the systematical study, it has been found that both the forward-and backward-facing steps have a destabilizing effect on the oncoming T-S waves in subsonic boundary layers, this effect increases with the height of the step and/or the frequency of the T-S wave, and a backward-facing step(BFS) always has a greater impact than a forward-facing step(FFS). These facts agree with most of the previous investigations.However, one numerical study(WORNER, A., RIST, U., and WAGNER, S. Humps/steps influence on stability characteristics of two-dimensional laminar boundary layer. AIAA Journal, 41, 192–197(2003)), which was based on an ad-hoc configuration, showed an opposite impact of an FFS. Through the investigation on the specific configuration, it is revealed that the wrong conclusion was drawn by misinterpreting the numerical results.

Cardiac and non-cardiac causes of T-wave inversion in the precordial leads in adult subjects: A Dutch case series and review of the literature

AIM: To describe the electrocardiographic(ECG) phenomena characterized by T-wave inversion in the precordial leads in adults and to highlight its differential diagnosis. METHODS: A retrospective chart review of 8 adult patients who were admitted with ECG T-wave inversion in the anterior chest leads with or without prolongation of corrected QT(QTc) interval. They had different clinical conditions. Each patient underwent appropriate clinical assessment including investigation for myocardial involvement. Single and multimodality noninvasive, semi-invasive and invasive diagnostic approach were used to ascertain the diagnosis. The diagnostic assessment included biochemical investigation, cardiac and abdominal ultrasound, cerebral and chest computed tomography, nuclear medicine and coronary angiography.RESULTS: Eight adult subjects(5 females) with a mean age of 66 years(range 51 to 82) are analyzed. The etiology of T-wave inversion in the precordial leads were diverse. On admission, all patients had normal blood pressure and the ECG showed sinus rhythm. Five patients showed marked prolongation of the QTc interval. The longest QTc interval(639 ms) was found in the patient with pheochromocytoma. Giant T-wave inversion(≥ 10 mm) was found in pheochromocytoma followed by electroconvulsive therapy and finally ischemic heart disease. The deepest T-wave was measured in lead V3(5 ×). In 3 patients presented with mild T-wave inversion(patients 1, 5 and 4 mm), the QTc interval was not prolonged(432, 409 and 424 msec), respectively.CONCLUSION: T-wave inversion associated with or without QTc prolongation requires meticulous history taking, physical examination and tailored diagnostic modalities to reach rapid and correct diagnosis to establish appropriate therapeutic intervention.

A METHOD FOR EPICENTER LOCATNG BY USING T WAVES

Two OBS arrays were deployed in the southern Okinawa Trough.Some of the OBS records revealedmany earthquakes with intensive T waves but ambiguous body waves.A new method using T waves for epicenter locating was developed that was found to be as precise as the body wave method for locatingepicenters when T waves are clearly recorded.

Crack Detection in Pipes with Different Bend Angles Based on Ultrasonic Guided Wave

Pipeline plays an indispensable role in process industries,because the progressing crack-like defects of in it may result in serious accidents and significant economic losses.Therefore,it is essential to detect the cracks occurred in pipelines.The axial crack-like defects in elbows with different angle are inspected by using the T(0,1)mode guided waves,in which different configurations including 45°,90°,135°and 180°(straight pipe)are considered respectively.Firstly,the detection sensitivity for different defect location is experimentally investigated.After that,finite element simulation is used to explore the propagation behaviors of T(0,1)mode in different bend structures.Simulation and experiment results show that the crack in different areas of the elbow can affect the detection sensitivity.It can be found that the detection sensitivity of crack in the middle area of the elbow is higher compared to the extrados and intrados of the elbow.Finally,the mode conversion is also investigated when the T(0,1)crosses the bend,and the results show that bend is a key factor to the mode conversion phenomenon which presents between the T(0,1)mode and F(1,2)mode.

A Broadband T/R Front-End of Millimeter Wave Holographic Imaging

A broadband T/R frond-end of active holographic imaging system is presented. Compact autodyne mode circuit structure front-end is adopted to achieve higher signal to noise ratio and higher reliability, which is beneficial to the after-end imagining. The factors that influence the dynamic range and the transverse resolution ratio of holographic imaging system have been analyzed. Wide-band oscillator, wide-band low noise amplifier and the tapered slot antennas are implemented to meet the requirements of the holographic imagining system. According to the measured results, the output power is uniform in the broadband working frequency. The sub-harmonic suppression is better than 25 dBc from the frequency of 28 GHz to 33 GHz. The isolation between antennas channel is greater than 20 dB. The experimental result shows that the performance of the front-end is good enough to meet the needs of active millimeter-wave holographic imaging system.

Measurement of T wave in magnetocardiography using tunnel magnetoresistance sensor

Several critical clinical applications of magnetocardiography(MCG)involve its T wave.The T wave’s accuracy directly affects the diagnostic accuracy of MCG for ischemic heart disease and arrhythmogenic.Tunnel magnetoresistance(TMR)attracts attention as a new MCG measurement technique.However,the T waves measured by TMR are often drowned in noise.The accuracy of T waves needs to be discussed to determine the clinical value of MCG measured by TMR.This study uses an improved empirical mode decomposition(EMD)algorithm and averaging to eliminate the noise in the MCG measured by TMR.The MCG signals measured by TMR are compared with MCG measured by the optically pumped magnetometer(OPM)to judge its accuracy.Using the MCG measured by OPM as a reference,the relative errors in time and amplitude of the T wave measured by TMR are 3.4%and 1.8%,respectively.This is the first demonstration that TMR can accurately measure the time and amplitude of MCG T waves.The ability to provide reliable T wave data illustrates the significant clinical application value of TMR in MCG measurement.

Analysis of the Q-T Dispersion and T Wave Alternans in Patients with Epilepsy

Objectives: There is a high rate of sudden death in epilepsy patients, part of which is sudden cardiac death. By investigating ECG T wave alternans and Q-T dispersion changes of epilepsy patients, we may predict the possibility of the occurrence of sudden death and provide basis for clinical prevention. Methods: Selecting 587 cases of epilepsy patients as the study group, 672 same period cases of healthy persons as the control group;Analyzing the effect of epilepsy on ECG T wave alternans and Q-T dispersion with the standard 12 lead ECG. Results: The study group had a significantly prolonged Q-T dispersion and an increased incidence of T wave alternans than that of the control group;Compared with other seizure types, tonic clonic seizure and absence seizure had a significantly prolonged Q-T dispersion and an increased occurrence rate of T wave alternans. Conclusions: Epilepsy patients ECG T wave alternans and Q-T dispersion has higher abnormal rate, and are prone to sudden cardiac death;Routine ECG(RECG) T wave alternans and Q-T dispersion changes can provide guidance for clinical prevention of sudden unexpected death in epilepsy (SUDEP).

Preoperative Atrial Fibrillation and T-Wave Inversion Associated with Postoperative Pulmonary Edema

Background: Atrial fibrillation (AF) and T wave inversion (TWI) are occasionally found on pre-operative electrocardiograms (EKG) of patients with long standing hy-pertension (HTN) associated with left ventricular hypertrophy (LVH). Each of these two pathologies, AF and LVH, can impose negative hemodynamic effects on the car-diac function. Case: We present a case of a patient with AF, TWI and long standing HTN that went into post-operative pulmonary edema. Conclusion: Even returning to base line poorly controlled hypertension, and even more so during a hypertensive cri-sis, their concurrent presence may inflict even more detrimental effect manifested by elevation of pulmonary venous pressure and pulmonary edema.

THE APPLICATION OF EVOLUTIONARY ALGORITHM IN DETERMINING T WAVE-END

There have been several methods for determining T wave-end. But none of them can overcome the difficulty from multiformity of ECG signal pattern. In this paper, a method for determining T wave-end using evolutionary algorithm (EA) is proposed. In this way, first, every characteristic parameter related to T wave-end is encoded to a string of codes, and adaptation function is constructed with the string of codes. Then choose the individual according to the adaptation function value and do genetic operation (reproduction, crossover and mutation), so as to produce offspring with more adaptation function value. Because of EA's autoadaptation and autoorganization character, it can trace ECG signal type and find the T wave-end automatically.Experiment results show that the error ratio of recognizing T wave-end using this method is much smaller than that using existing method.

The Relationship between Changes of Polarity of the T Waves and Left Ventricular Function after Acute Anterior Myocardial Infarction

Objective To explore therelation between changes of T waves and left ventricular function in patients with Q - wave anterior wall MI. Methods 105 consecutive patients with Q-wave anterior wall MI were enrolled in this study. These patients were divided into two groups according to the polarity of T wave at 6 months: negative T - wave group (n=45) and positive T-wave group (n = 60) . Electrocardiograms were recorded and echocardiogra-phy was performed on admission and at 6 months after anterior MI. Results The peak serum creatine ki-nase activity of negative T - wave group and positive T -wave group was (4158 ±2478) IU/L and (2868±2358) IU/L, respectively (P < 0. 05). Left ventricular function was better in positive T - wave group than negative T - wave group. Conclusion Earlier normalization of the precordial T waves was associated with greater improvement in LV function. The early presence of inverted T waves in leads with abnormal Q waves can be used to assess the degree of LV dysfunction.

基于慢性心肌缺血小鼠模型探究心电图T波低平的电生理机制

目的 建立通过稳定的冠心病慢性心肌缺血小鼠模型,初步阐述缺血状态下T波低平的电生理原理。方法 将APOE-/-小鼠随机分为模型组和降脂药(lipid-lowering drug, LLD)组,高脂饮食喂养3个月,同时设立C57BL/6J小鼠作为空白组。检测造模前后小鼠心电图变化,通过核素PET/CT扫描评估心脏血流灌注情况,使用主动脉苏木伊红(hematoxylin-eosin, HE)染色和油红染色评估斑块动脉粥样硬化(atherosclerosis, AS)病理。同时,分离小鼠心肌细胞并记录心肌细胞动作电位。结果 高脂喂养3个月后模型组小鼠的胆固醇(cholesterol, CHO)和低密度脂蛋白(low-density lipoprotein, LDL-C)显著升高,同时主动脉出现脂质斑块。LLD组病变减少,空白组无斑块。心肌核素扫描显示模型组小鼠的心肌血流灌注显著低于LLD组和空白组。小鼠心电图显示模型组和LLD组的T/QRS显著降低,空白组无明显改变。记录心肌细胞动作电位发现,缺血的内层心肌细胞复极速率增加,内外电位差减小是T波低平的主要电生理机制。结论 APOE-/-小鼠可用于慢性心肌缺血小鼠模型,缺血状态下内层心肌复极速率的增加可能是心电图中T波降低的主要原因。

冠心病患者动态心电图检查中P波离散度、T波峰-末间期的变化及诊断价值研究

目的:探讨冠心病(CHD)患者动态心电图检查中P波离散度(Pd)、T波峰-末(Tp-Te)间期的变化及诊断价值。方法:选取CHD患者203例作为研究组,其中,心肌缺血95例作为心肌缺血组,心肌缺血合并心律失常108例作为心肌缺血合并心律失常组。另取同期体检健康者90例作为对照组。所有受试者均接受动态心电图检查,并记录Pd、Tp-Te间期情况。比较研究组和对照组以及心肌缺血组和心肌缺血合并心律失常组Pd、Tp-Te间期。绘制受试者工作特征曲线(ROC)分析Pd、Tp-Te间期对CHD及CHD心律失常的诊断价值。结果:研究组Pd、Tp-Te间期大于对照组(均P<0.05)。Pd、Tp-Te间期联合诊断CHD的AUC高于两者单独诊断的AUC(均P<0.05)。心肌缺血合并心律失常组Pd、Tp-Te间期大于心肌缺血组(均P<0.05)。Pd、Tp-Te间期联合诊断CHD患者心律失常的AUC高于两者单独诊断的AUC(均P<0.05)。结论:CHD患者动态心电图Pd增加及Tp-Te间期延长,且心肌缺血合并心律失常患者Pd增加及Tp-Te间期延长较心肌缺血患者更为明显,两者联合对CHD及CHD心律失常诊断价值较高。