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.

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.

The Relationship between T-Wave Alternans and Adverse Cardiac Events in Patients with Congenital Long QT Syndrome:A Systematic Review and Meta-Analysis

Background:T-wave alternans(TWA)is a risk factor of ventricular arrhythmias or sudden cardiac death(SCD)in patients with ischemic cardiomyopathy.Nevertheless,the relationship between TWA and adverse cardiac events(ACE)in patients with congenital long QT syndrome(LQT)remains controversial.Methods:A systematic electronic search of PubMed,Embase and the Cochrane Library was conducted from database inception dates to 28 April 2021 and assessed the relationship between TWA and ACE in patients with LQTS.Sub-group analysis evaluated the association between microvolt TWA(MTWA)and ACE in different monitoring models and ECGlead numbers.Results:A pooled analysis of seven studies of 625 patients with LQTS showed that TWA was significantly associated with ACE(OR 3.16,95%CI 1.86–5.37,P<0.001).Advanced analysis showed that macroscopic TWA was significantly related to ACE(OR 6.01,95%CI 2.96–12.21,P<0.001),while MTWA did not(OR 0.92,95%CI 0.37–2.30,P=0.85).Sub-group analysis showed that MTWA recorded in 24 h continuous ECG(OR 6.79,95%CI 0.80–57.75,P=0.08)might have a stronger association with ACE than recorded in stress ECG(OR 0.28,95%CI 0.07–1.10,P=0.07).No difference was observed between MTWA measured in multi-lead ECG and limited ECG leads(P=0.15).Conclusions:Macroscopic TWA was significantly related to ACE in patients with LQTS.In terms of MTWA,MTWA recorded in 24 h continuous ECG might have a stronger association with ACE than stress ECG,but still deserves further evaluation.

Detection of T-wave Alternans in ECG Signals Using FRFT and Tensor Decomposition

T-wave alternans(TWA)refers to the periodic beat-to-beat variation in the amplitude of T-wave in the electrocardiogram(ECG)signal in an ABAB-pattern.TWA has been proven to be a very important indicator of malignant arrhythmia risk stratification.A new method to detect TWA by combining fractional Fourier transform(FRFT)and tensor decomposition is proposed.First,the T-wave vector is extracted from the ECG of each heartbeat,and its FRFT amplitudes at multiple orders are arranged to form a T-wave matrix.Then,a third-order tensor is composed of T-wave matrices of several consecutive heart beats.After tensor decomposition,projection matrices are obtained in three dimensions.The complexity of the projection matrix is measured by Shannon entropy to obtain feature vector to detect the presence of TWA.Results show that the sensitivity,specificity,and accuracy of the algorithm on the MIT-BIH database are 91.16%,94.25%,and 92.68%,respectively.This method effectively utilizes the fractional domain information of ECG,and shows the promising potential of the FRFT in ECG signal processing.

Adaptive Match-Filtering: A Biomedical Application to Identify T-Wave Alternans

T-wave alternans (TWA), consisting in an alternation of the electrocardiographic (ECG) repolarization segment (T-wave), is a promising index of the risk of sudden cardiac death. By definition, it is characterized by a frequency component, termed fTWA, that matches half heart rate. The heart-rate adaptive match filter (AMF) based method is a technique for automatic TWA identification from the digital ECG. Aim of the present study was to provide a complete technical description of the filter able to explain its methodological principles. The AMF is usually realized as a 6th order Butterworth filter with a narrow (0.12 Hz) passing band centered in fTWA. It is applied in a bidirectional fashion, so that final filtering order is 12. While extracting the TWA component, the AMF simultaneously filters out every ECG component including noise and artefacts, and thus results are very robust. Goodness of the technique was tested using 8 synthetic ECG tracings corrupted by typical noisy factors, such as white random noise, baseline wanderings, heart-rate variability, and others. Six ECG tracings were affected by 100 μV TWA, whereas two were not. Results indicate that the AMF-based method is able to prevent false-positive and false-negative detections and, thus, represents a useful tool for a reliable TWA identification.

On the basis of the morphology of the T-wave alternans: A Poincare mapping method research

Presently T-wave alternans (TWA) has become a clinical index of non-invasive diagnosis for heart sudden death prediction, and detecting T-wave alternate accurately is particularly important. This paper introduces an algorithm for detecting TWA using Poincare mapping method which is a technique for nonlinear dynamic systems to display periodic behavior. Sample series of beat to beat cycles were selected to prepare Poincare mapping method. Vector Angle Index (VAI), which is the mean of the difference between θi (the angle between the line connecting the i point to the origin and the X axis) and 45 degrees was used to present the presence or absence of TWA. The value of 0.9 rad ≤ VAI ≤ 1.03 rad is accepted as a level determinative for presence of TWA. VAI via Poincare mapping method (PM) is used for correlation analysis with T-wave alternans voltage (Vtwa) by way of the spectral method (SM). The cross-correlation coefficient between Vtwa and VAI is γ = 0.8601. The algorithm can identify the absence and presence of TWA accurately and provide idea for further study of TWA-PM.

Application of T-Wave Alternans in Evaluation of Prognosis in Patients with Intracerebral Hemorrhage

Objective: To explore the application value of electrocardiograph (ECG) T-wave Alternans (TWA) anomaly in acute stage of intracerebral hemorrhage patients. Methods: We choose 1175 intracerebral hemorrhage patients whose conventional 12-lead ECG has TWA in our hospital from January 2011 to December 2015, 751 patients without TWA in the same period as the control group, compared the volume of intracerebral hemorrhage, bleeding site and mortality between the 2 groups. Results: In TWA group, 247 cases died, 361 cases with massive intracerebral hemorrhage, 298 cases with brain stem hemorrhage;in TWA negative group (control group), 41 cases died, 93 cases with massive brain hemorrhage, 64 cases with brain stem hemorrhage. There are statistical differences between two groups (P Conclusion: The occurrence of TWA is significantly related to the volume of bleeding, the bleeding site and mortality, and can be used as an important parameter in the prognosis of intracerebral hemorrhage.

誓约的记忆秋之回忆6T-wave

从第一部《秋之回忆》发售至今，已然十年。在这十年中，KID以及它的继承者5pb为我们带来了包括正传、外传和后续故事在内的十三部作品。初代、雪莹、想君和从今以后的巅峰，中断胶片的争议，安可的质疑，无疑不深深刺激着玩家的心里。

空心莲子草皂苷的微波辅助提取工艺

目的:确定空心莲子草皂苷最佳提取工艺。方法:采用微波辅助法提取空心莲子草中的皂苷类化合物,通过正交试验确定最佳提取工艺;以齐墩果酸为对照,采用分光光度法在570nm波长处测定其中的皂苷,回归方程为:Y=1.904C+0.0054,r=0.9990。结果:最佳工艺条件为20%的甲醇、固液比1:20(g/mL)、微波时间20s、微波功率640W、间歇提取4次。结论:选出了空心莲子草皂苷的最佳提取工艺,用齐墩果酸做标准品,采用分光光度法测定皂苷含量,操作简便,结果准确。

T波电交替在恶性心律失常中的预测

目的对T波电交替(TWA)恶性心律失常进行相关性分析。方法60例TWA的患者作为交替组;无"T"波交替者60例作为对照组,对照分析动态心电图恶性心律失常发生情况。结果交替组心律失常发生率明显高于对照组(P<0.05)。观察组恶性室性心律失常致死者7例,对照组2例。结论TWA对预测恶性心律失常有重要价值。

微伏级T波电交替与急性心肌梗死患者恶性心律失常的相关性研究

目的评估微伏级T波电交替与急性心肌梗死(AMI)患者恶性心律失常的相关性。方法入选89例AMI患者,并根据住院期间是否发生恶性心律失常分为恶性心律失常亚组及无恶性心律失常亚组,另选来我院健康体检的非心肌梗死患者80例入选对照组,对比分析其MTWA最大值、LVEF、心率变异性SDNN值。结果急性心肌梗死组MTWA最大值高于对照组,而LVEF值、心率变异性SDNN值低于对照组。急性心肌梗死两亚组间比较,恶性心律失常亚组MTWA最大值高于无恶性心律失常亚组,而LVEF值、心率变异性SDNN值低于无恶性心律失常亚组。差异有统计学意义(P>0.05)。结论 MTWA最大值、LVEF和心率变异性与AMI患者住院期间恶性心律失常的发生有相关性,可用于AMI患者的危险分层。

冠心病患者窦性心率震荡及T波电交替与心率变异性的相关性分析

目的探讨冠心病患者窦性心率震荡(HRT),心率变异性(HRV)及T波电交替(TWA)变化及相关性。方法冠状动脉造影诊断为冠心病患者(冠心病组)137例,其中陈旧性心肌梗死组50例,稳定性心绞痛组87例;选择同期健康体检者101例为对照组。24h动态心电图检测各组HRT、HRV和TWA参数,进行相关性分析。结果冠心病组与对照组比较,TO值显著增高,TS值显著下降,HRV指标(SDANN,ASDNN,VLF,LF,TP,LF/HF)值显著下降,差异有统计学意义(均P<0.01);最大TWA值增大,在MV5,MV1导联差异有统计学意义(均P<0.01)。陈旧性心肌梗死组与稳定性心绞痛组比较,TS值显著下降,HRV指标(SDANN,ASDNN,VLF、LF、HF、TP)值显著降低,差异有统计学意义(均P<0.05)。TO与SDNN、ASDNN、VLF呈负相关(r=-0.18^-0.19,P<0.05),TS与VLF、LF、HF、TP、SDANN、ASDNN、rMSSD、PNN50呈正相关(r=0.22~0.46,均P<0.01)。结论同时对HRT、HRV及TWA参数比对评估,可提高对冠心病患者危险性评估的准确性和可靠性。

陈旧性心肌梗死患者的微伏级T波电交替

目的研究陈旧性心肌梗死(简称心梗)患者的微伏级T波电交替(MTWA),旨在探讨MTWA的临床意义。方法平板运动试验过程中利用渐量修正技术监测陈旧性心梗患者83例(Ⅰ组,依试验过程中有无室性心律失常发生分为Ⅰa、Ⅰb组),健康人群90例(Ⅱ组)的MTWA,分析各组之间MTWA的差异及MTWA与心梗部位的相关性。结果①各导联组间MTWA除aVR导联三组间无差异外,余导联均有差异;②Ⅰa组与Ⅱ组除aVL导联外余各导联MTWA值无差异(P>0.017);Ⅰa组与Ⅰb组Ⅱ、Ⅲ、aVF导联MTWA值有差异(P<0.017),余各导联MTWA值无差异(P>0.017);Ⅱ组与Ⅰb组各导联MTWA值有差异(P<0.017)。③Ⅰb组不同部位心梗的相关导联MTWA值有差异。结论MTWA可作为陈旧性心梗患者发生恶性室性心律失常危险分层的指标。

雷诺嗪抗房颤和室颤的机制研究进展

冠心病和心衰有并发房颤和致命性室性心律失常的危险。研究证实,雷诺嗪在治疗浓度下对这些心律失常有强效的抑制作用。本文就雷诺嗪抗颤动作用的机制和临床应用作一综述。

Entire process of electrocardiogram recording of Wellens syndrome:A case report

BACKGROUND Wellens syndrome is an electrocardiogram(ECG)pattern seen in high-risk patients with unstable angina pectoris.It is characterized by inverted or biphasic T-waves that change into positive or pseudo-normalized waves at precordial leads when the patient experiences an angina attack;however,the mechanism for this condition remains unclear.CASE SUMMARY A 47-year-old male patient experienced repeated,unprovoked episodes of chest pain for>20 d,with worsening during the previous day.On the day of admission,he experienced episodes of paroxysmal chest pain lasting more than 30 min,in addition to radiating pain to the left arm and exertional dyspnea.The patient presented to the emergency department with no chest pain or other discomfort at that time.ECG at presentation showed sinus tachycardia and Twave changes,which were identified as Wellens syndrome when combined with previous ECG findings.ECGs and myocardial enzymology examinations were normal when angina was present,but the ECG showed inverted or biphasic Twaves when angina was absent.After percutaneous coronary intervention,the ECGs demonstrated inverted or biphasic T-waves in the anterior precordial leads on days 0,1,and 2,but normal T-waves on day 3.The ECGs showed no subsequent ischemic ST-T-wave changes.CONCLUSION The Wellens syndrome pseudo-normalized T-waves likely reflect development of unstable angina pectoris into the hyperacute phase of ST-segment elevation myocardial infarction.

便携式T波交替检测系统

设计一种便携式心电监护系统,该系统通过穿戴式心电监护终端采集患者体表心电信号,经过A/D转换成数字信号后通过分离式的蓝牙技术将数据传输到PC机,采用基于SM和MMA算法的分析软件对T波交替现象进行检测和判定。

Microvolt T-wave alternans complemented with electrophysiologic study for prediction of ventricular tachyarrhythmias in patients with arrhythmogenic right ventricular cardiomyopathy: a long-term follow-up study

Background: The long-term predicted value of microvolt T-wave alternans (MTWA) for ventricular tachyarrhythmia in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) remains unclear. Our study explored the characteristics of MTWA and its prognostic value when combined with an electrophysiologic study (EPS) in patients with ARVC. Methods: All patients underwent non-invasive MTWA examination with modified moving average (MMA) analysis and an EPS. A positive event was defined as the first occurrence of sudden cardiac death, documented sustained ventricular tachycardia (VT), ventricular fibrillation, or the administration of appropriate implantable cardioverter defibrillator therapy including shock or antitachycardia pacing. Results: Thirty-five patients with ARVC (age 38.6 ± 11.0 years;28 males) with preserved left ventricular (LV) function were recruited. The maximal TWA value (MaxValt) was 17.0 (11.0–27.0)μV. Sustained VT was induced in 22 patients by the EPS. During a median follow-up of 99.9 ± 7.7 months, 15 patients had positive clinical events. When inducible VT was combined with the MaxValt, the area under the curve improved from 0.739 to 0.797. The receiver operating characteristic curve showed that a MaxValt of 23.5 μV was the optimal cutoff value to identify positive events. The multivariate Cox regression model for survival showed that MTWA (MaxValt, hazard ratio [HR], 1.06;95% confidence interval [CI], 1.01–1.11;P = 0.01) and inducible VT (HR, 5.98;95% CI, 1.33–26.8;P = 0.01) independently predicted positive events in patients with ARVC. Conclusions: MTWA assessment with MMA analysis complemented by an EPS might provide improved prognostic ability in patients with ARVC with preserved LV function during long-term follow-up.

T-wave oversensing and inappropriate shocks in implantable cardioverter defibrillators

The implantable cardioverter defibrillator （ICD） represents today the treatment and prophylaxis of choice for patients at risk for sustained ventricular tachyarrhythmias.1-6 Accurate sensing of ventricular tachyarrhythmias is a critical aspect of the function of ICD. All currently available models include algorithms with variable sensitivity, allowing adjustments which optimize the detection of low amplitude signals during ventricular tachyarrhythmia. However,

基于相关分析方法的非稳态心电T波交替检测研究

目的:研究T波段幅度、形态逐拍交替变化的心电变异现象检测。方法:本研究首先使用Mexican-hat小波检测R峰并对心电信号进行预处理;在提取T波矩阵方面为减少心拍间内差,采用点乘最大法,最大程度地对齐T波;最后基于时域相关分析方法检测T波交替幅度、交替心拍,追踪非稳态心电信号中短暂的交替数据段。结果:利用相关分析法对样本数据所测交替幅度与谱分析法相比更加显著,并且可以检测出谱分析方法无法检测的交替心拍。结论:时域相关分析方法能够更精确地追踪T波交替随时间变化的现象,但其对输入数据要求较高,因此在检测中可以先通过谱分析方法检测为阳性TWA的基础上,再对心电信号进行相关分析,从而确定非稳态交替时间段和更加准确的交替幅度。

微伏T波电交替对STEMI患者PCI术后室性心律失常的预测价值

目的：探讨微伏T波电交替增高与STEMI患者PCI术后室性心律失常的发生关系。方法：选择我院2011年4月-2013年4月收治的68例STEMI患者，所有患者均成功进行了直接PCI，且阻塞远端血流均达到TIMI3级。所有患者于手术后进行了24小时动态心电图检查，并测定微伏T波电交替值。结果：36例发生NSVT患者较未发生32例患者最大微伏T波电交替明显升高，（68．1±6．4VS31．9±3．8μV，P〈0．05）。最大T波电交替值大于45μV预测非持续性室速发生的敏感性为75％，特异性为72％；阳性预测值为70％。阴性预测值77％（AUC=0．84）。经过进一步比较分析发现，ST段抬高的程度与非持续室速的发生无关（AUC=0．61）。结论：微伏T波电交替可预测STEMI患者PCI术后室性心律失常的发生。