BACKGROUND & AIMS: :Myocardial infarction (MI) is among the leading causes of death in the United States. It is imperative to identify and characterize MIs for timely delivery of life-saving medical interventions. Cardiac electrical activity propagates in space and evolves over time. Traditional works focus on the analysis of time-domain ECG (e.g., 12-lead ECG) on the body surface for the detection of MIs, but tend to overlook spatiotemporal dynamics in the heart. Body surface potential mappings (BSPMs) provide high-resolution distribution of electric potentials over the entire torso, and therefore provide richer information than 12-lead ECG. However, BSPM are available on the body surface. Clinicians are in need of a closer look of the electric potentials in the heart to investigate cardiac pathology and optimize treatment strategies. In this paper, we applied the method of spatiotemporal inverse ECG (ST-iECG) modeling to map electrical potentials from the body surface to the heart, and then characterize the location and extent of MIs by investigating the reconstructed heart-surface electrograms. First, we investigate the impact of mesh resolution on the inverse ECG modeling. Second, we solve the inverse ECG problem and reconstruct heart-surface electrograms using the ST-iECG model. Finally, we propose a wavelet-clustering method to investigate the pathological behaviors of heart-surface electrograms, and thereby characterize the extent and location of MIs. The proposed methodology is evaluated and validated with real data of MIs from human subjects. Experimental results show that negative QRS waves in heart-surface electrograms indicate potential regions of MI, and the proposed ST-iECG model yields superior characterization results of MIs on the heart surface over existing methods.

背景与目标： ：心肌梗塞（MI）是美国的主要死亡原因之一。当务之急是识别和表征心梗，以及时提供挽救生命的医疗干预措施。心脏电活动在空间中传播并随时间发展。传统工作着重于分析体表上的时域心电图（例如12导联心电图）以检测心梗，但往往忽略了心脏的时空动态。体表电位映射（BSPM）可在整个躯干上提供高分辨率的电位分布，因此比12导联ECG可以提供更丰富的信息。但是，BSPM可以在体表上使用。临床医生需要仔细查看心脏中的电势，以研究心脏病理并优化治疗策略。在本文中，我们应用时空逆心电图（ST-iECG）建模方法来绘制从体表到心脏的电势，然后通过研究重建的心脏表面电描记图来描述MI的位置和范围。首先，我们研究了网格分辨率对反ECG建模的影响。其次，我们解决反心电图问题，并使用ST-iECG模型重建心脏表面电图。最后，我们提出了一种小波聚类方法来研究心脏表面电描记图的病理行为，从而表征心梗的程度和位置。利用来自人类受试者的MI的真实数据对提出的方法进行评估和验证。实验结果表明，心脏表面电描记图上的负QRS波指示了MI的潜在区域，与现有方法相比，所提出的ST-iECG模型在心脏表面产生了MI的更好的表征结果。

BACKGROUND & AIMS: :Background: Left ventricular hypertrophy (LVH) is an important risk factor for cardiovascular events. The electrocardiography (ECG) has poor sensitivity, but it is commonly used to detect LVH. AIM:To evaluate the diagnostic efficacy of known ECG indicators to recognize LVH in subgroups with different cardiovascular risk levels. Methods: 676 volunteers were included. RESULTS:We found that 10.2% of the analyzed population had LVH based on echocardiography. Individuals with LVH were older, had a higher body mass index, higher systolic blood pressure, lower heart rate, higher parameters of insulin resistance, higher cardiovascular risk, and android-type obesity. Variables that remained independently associated with LVH were QRS duration, left atrial volume index, troponin T, and hemoglobin A1c. The receiver operating characteristics (ROC) curve analysis of the Sokolow-Lyon index did not show a significant predictive ability to diagnose LVH in the whole study population including all cardiovascular risk classes. The ROC curves analysis of Cornell and Lewis indices showed a modest predictive ability to diagnose LVH in the general population and in a low cardiovascular class. CONCLUSIONS:There is a need for new, simple methods to diagnose LVH in the general population in order to properly evaluate cardiovascular risk and introduce optimal medical treatment of concomitant disease.

背景与目标： 背景：左心室肥大（LVH）是心血管事件的重要危险因素。心电图（ECG）灵敏度较差，但通常用于检测LVH。
目的：评估已知心电图指标在不同心血管风险水平亚组中识别LVH的诊断功效。方法：纳入676名志愿者。
结果：我们发现，根据超声心动图，所分析的人群中有10.2％患有LVH。 LVH患者年龄较大，体重指数较高，收缩压较高，心率较低，胰岛素抵抗参数较高，心血管疾病风险较高，机器人型肥胖。与LVH保持独立相关的变量包括QRS持续时间，左心房容积指数，肌钙蛋白T和血红蛋白A1c。 Sokolow-Lyon指数的接受者工作特征（ROC）曲线分析未显示出在包括所有心血管风险类别在内的整个研究人群中诊断LVH的显着预测能力。康奈尔和刘易斯指数的ROC曲线分析显示，在一般人群和低心血管疾病人群中，LVH诊断的预测能力中等。
结论：需要一种新的，简单的方法来诊断普通人群中的LVH，以正确评估心血管疾病的风险并引入伴随疾病的最佳药物治疗。

BACKGROUND & AIMS: :In the framework of the electrocardiography (ECG) signals, this paper describes an original approach to identify heartbeat morphologies and to detect R-wave events. The proposed approach is based on a "geometrical matching" rule evaluated using a decision function in a local moving-window procedure. The decision function is a normalized measurement of a similarity criterion comparing the windowed input signal with the reference beat-pattern into a nonlinear-curve space. A polynomial expansion model describes the reference pattern. For the curve space, an algebraic-fitting distance is built according to the canonical equation of the unit circle. The geometrical matching approach operates in two stages, i.e., training and detection ones. In the first stage, a learning-method based on genetic algorithms allows us estimating the decision function from training beat-pattern. In the second stage, a level-detection algorithm evaluates the decision function to establish the threshold of similarity between the reference pattern and the input signal. Finally, the findings for the MIT-BIH Arrhythmia Database present about 98% of sensitivity and 99% of positive predictivity for the R-waves detection, using low-order polynomial models.

背景与目标： 在心电图（ECG）信号的框架中，本文介绍了一种识别心跳形态和检测R波事件的原始方法。所提出的方法基于在本地移动窗口过程中使用决策函数评估的“几何匹配”规则。决策函数是相似性标准的归一化测量，它将加窗的输入信号与参考拍子模式比较成非线性曲线空间。多项式展开模型描述了参考模式。对于曲线空间，根据单位圆的正则方程建立代数拟合距离。几何匹配方法分为两个阶段，即训练和检测两个阶段。在第一阶段，基于遗传算法的学习方法使我们能够从训练节拍模式中估计决策函数。在第二阶段，电平检测算法评估决策函数，以建立参考模式与输入信号之间相似度的阈值。最后，使用低阶多项式模型，MIT-BIH心律失常数据库的发现显示R波检测的灵敏度约为98％，阳性预测值为99％。

BACKGROUND & AIMS: :Tea catechins, the main bioactive polyphenols in green tea, are well known for their health promoting effects. Previous studies have shown that gallocatechin-3-gallate (GCG), epigallocatechin-3-gallate (EGCG) and epicatechin-3-gallate (ECG) exerted strong inhibitory effects on mushroom tyrosinase activity in vitro, whilst EGCG inhibited melanogenesis in vivo, yet the underlying mechanisms are not entirely clear. In this study, we (i) evaluated and compared the inhibitory effects of the main tea catechins (GCG, EGCG, and ECG) on melanogenesis in B16F10 melanoma cells, and (ii) explain the underlying mechanisms. The results showed that the tea catechins significantly suppressed tyrosinase activity and melanin synthesis in B16F10 cells, where the effects of ECG > EGCG > GCG. Interestingly, the inhibitory effects of the catechins were stronger than those of arbutin (AT), a well-known depigmenting agent. Moreover, GCG, EGCG, and ECG regulated the melanogenesis of B16F10 cells through the cAMP/CREB/MITF pathway. These results revealed catechins could be used as anti-melanogenic agents to protect cells from abnormal melanogenesis.

背景与目标： 儿茶素是绿茶中的主要生物活性多酚，以其促进健康的作用而闻名。先前的研究表明，加洛儿茶素-3-没食子酸酯（GCG），表没食子儿茶素-3-没食子酸酯（EGCG）和表儿茶素-3-没食子酸酯（ECG）在体外对蘑菇酪氨酸酶活性具有很强的抑制作用，而EGCG却在体内抑制黑素生成。潜在的机制尚不完全清楚。在这项研究中，我们（i）评估并比较了主要茶儿茶素（GCG，EGCG和ECG）对B16F10黑色素瘤细胞中黑色素生成的抑制作用，并且（ii）解释了其潜在机制。结果表明，茶儿茶素能显着抑制B16F10细胞中的酪氨酸酶活性和黑色素合成，其中ECG> EGCG> GCG的作用。有趣的是，儿茶素的抑制作用比众所周知的色素去除剂熊果苷（AT）强。此外，GCG，EGCG和ECG通过cAMP / CREB ​​/ MITF途径调节B16F10细胞的黑色素生成。这些结果表明，儿茶素可以用作抗黑色素生成剂，以保护细胞免受异常黑色素生成的侵害。

BACKGROUND & AIMS: OBJECTIVE:We propose a non-invasive method for diagnosing post-capillary pulmonary hypertension (PH group 2). We evaluated pulmonary capillary wedge pressure (PCWP) by studying the left atrium (LA) on thoracic ECG-gated CT compared with right heart catheterisation (RHC). METHODS:We retrospectively studied 54 patients with suspected PH or followed for PH who underwent thoracic ECG-gated CT and RHC within 15 days. The diagnostic accuracy of CT morphological and functional data of the LA for the detection of PCWP >15 mmHg, evaluated by two independent readers, was assessed using correlation and receiver-operating characteristic (ROC) analysis. RESULTS:Interobserver agreement was high (r = 0.97-0.99). Correlations were found between PCWP and the morphological criteria of the LA such as anteroposterior diameter at 0 % of the R-R interval (r = 0.70, P ≤ 0.001) as well as at 40 % (r = 0.69, P ≤ 0.001). ROC curves constructed with a threshold value of PCWP > 15 mmHg showed an area under the curve between 0.88 and 0.91. Significant correlations were found between PCWP and functional criteria of the LA, including distensibility (r = -0.49, P ≤ 0.001) and ejection fraction (r = -0.58, P ≤ 0.001). CONCLUSION:Thoracic ECG-gated CT in a PH workup helps distinguish between pre- and post-capillary PH. KEY POINTS:• Computed tomography may help differentiate the various types of pulmonary hypertension (PH). • Post-capillary PH group 2 is due to left heart disease. • Right heart catheterisation is used to separate pre- and post-capillary PH. • Left atrium anteroposterior diameter measured on CT is of value. • ECG-gated CT helps clinicians to assess patients with PH non-invasively.

背景与目标： 目的：我们提出了一种非侵入性的方法来诊断毛细血管后肺动脉高压（PH 2组）。我们通过研究胸腔心电图CT上的左心房（LA）与右心导管（RHC）的比较来评估肺毛细血管楔压（PCWP）。
方法：我们回顾性研究了54例疑似PH或随访PH的患者，这些患者在15天内接受了胸部ECG门控CT和RHC检查。使用相关性和接收者操作特征（ROC）分析评估了两个独立阅读器评估的LA的CT形态学和功能数据对PCWP> 15 mmHg的诊断准确性。
结果：观察员之间的同意率很高（r = 0.97-0.99）。发现PCWP与LA的形态标准之间存在相关性，例如前后间隙在R-R间隔的0％（r = 0.70，P，≤0.001）和40％（r = 0.69，P≤0.001）时。用PCWP> 15 mmHg的阈值构建的ROC曲线显示曲线下的面积在0.88和0.91之间。发现PCWP与洛杉矶功能标准之间存在显着相关性，包括扩张性（r = -0.49，P≤0.001）和射血分数（r = -0.58，P≤0.001）。
结论：在胸腔镜检查中，胸心电门控CT有助于区分毛细血管扩张前后。
要点：•计算机断层扫描可能有助于区分各种类型的肺动脉高压（PH）。 •毛细血管后PH 2组归因于左心疾病。 •右心导管检查可用于分离毛细管前后的PH。 •CT测得的左心房前后直径很重要。 •ECG门控CT帮助临床医生无创地评估PH患者。

BACKGROUND & AIMS: OBJECTIVE:Because the International left atrial enlargement electrocardiographic (ECG) screening criteria (ECG-LAE) for athletes are rarely fulfilled in young athletes, we compared it with evidence-based criteria from a recent clinical outcome study of ECG left atrial abnormality (ECG-LAA). DESIGN:Retrospective analyses. SETTING:Routine preparticipation ECG screening in California. PARTICIPANTS:Four thousand four hundred thirty-eight young individuals (18.5 ± 5.4 years, 40% women). ASSESSMENT OF RISK FACTORS:The International criteria for ECG-LAE were applied: prolonged P wave duration of ≥120 ms in leads I or II AND negative portion of ≥1 mm in depth in lead V1. This was compared with Stanford criteria for ECG-LAA: prolonged P wave duration of ≥140 ms odds ratio (OR) negative portion in V1 and V2 greater than 1 mm. MAIN OUTCOME MEASURES:Differences in the classification of abnormal ECGs between the 2 criteria applied to the same population of young athletes. RESULTS:Only 33 (0.7%) of our subjects fulfilled the International criteria for ECG-LAE while 110 (2.5%) fulfilled the ECG-LAA criteria. Adding our new ECG-LAA criterion and considering it a major criterion raised the abnormal ECG prevalence and athletes referred for further evaluation from 2.9% to 4.4%. CONCLUSIONS:The Stanford evidence-based criterion for ECG-LAA incorporating V2 and replacing "or" for "and" regarding P wave duration increased the yield of abnormal classification for P waves. Future follow-up studies are needed to confirm that this new criterion should be included in future ECG screening consensus documents.

背景与目标： 目的：由于国际上很少针对年轻运动员满足运动员的国际左心房扩大心电图（ECG-LAE）筛查标准（ECG-LAE），因此，我们将其与最近进行的ECG左心室异常（ECG- LAA）。
设计：回顾性分析。
地点：加州常规的参与性心电图筛查。
参与者：448.38个年轻人（18.5±5.4岁，女性占40％）。
危险因素评估：采用ECG-LAE的国际标准：I或II导线延长P波持续时间≥120ms，V1导线深度≥1 mm负值。将此与ECG-LAA的斯坦福标准进行了比较：V1和V2中延长的P波持续时间≥140 ms比值比（OR）负部分大于1 mm。
主要观察指标：适用于同一年龄段年轻运动员的2项标准对异常心电图的分类存在差异。
结果：只有33（0.7％）名受试者符合ECG-LAA的国际标准，而110名（2.5％）符合ECG-LAA的国际标准。添加我们的新ECG-LAA标准并将其视为主要标准会提高异常心电图患病率，运动员转介进一步评估的比例从2.9％增至4.4％。
结论：斯坦福基于证据的ECG-LAA纳入V2并在P波持续时间上用“或”替换“和”的标准增加了P波异常分类的产生。需要进行进一步的随访研究，以确认该新标准应包括在未来的ECG筛查共识文件中。

BACKGROUND & AIMS: BACKGROUND:Globally, the cases of diabetes mellitus (diabetes) have increased in the past three decades, and it is recorded as one of the leading cause of death. This epidemic is a metabolic condition where the body cannot regulate blood glucose, thereby leading to abnormally high blood sugar. Genetic condition plays a significant role to determine a person susceptibility to the condition, a sedentary lifestyle and an unhealthy diet are behaviour that supports the current global epidemic. The complication that arises from diabetes includes loss of vision, peripheral neuropathy, cardiovascular complications and so on. Victims of this condition require constant monitoring of blood glucose which is done by the pricking of the finger. This procedure is painful, inconvenient and can lead to disease infection. Therefore, it is important to find a way to measure blood glucose non-invasively to minimize or eliminate the disadvantages encountered with the usual monitoring of blood glucose. METHOD:In this paper, we performed two experiments on 16 participants while electrocardiogram (ECG) data was continuously captured. In the first experiment, participants are required to consume 75 g of anhydrous glucose solution (oral glucose tolerance test) and the second experiment, no glucose solution was taken. We explored statistical and spectral analysis on HRV, HR, R-H, P-H, PRQ, QRS, QT, QTC and ST segments derived from ECG signal to investigate which segments should be considered for the possibility of achieving non-invasive blood glucose monitoring. In the statistical analysis, we examined the pattern of the data with the boxplot technique to reveal the change in the statistical properties of the data. Power spectral density estimation was adopted for the spectral analysis to show the frequency distribution of the data. RESULTS:HRV segment obtained a statistical score of 81% for decreasing pattern and HR segment have the same statistical score for increasing pattern among the participants in the first quartile, median and mean properties. While ST segment has a statistical score of 81% for decreasing pattern in the third quartile, QT segment has 81% for increasing pattern for the median. From a total change score of 6, ST, QT, PRQ, P-H, HR and HRV obtained 4, 5, 4, 5 and 6 respectively. For spectral analysis, HRV and HR segment scored 81 and 75% respectively. ST, QT, PRQ have 75, 62 and 68% respectively. CONCLUSIONS:The results obtained demonstrate that HR, HRV, PRQ, QT and ST segments under a normal, healthy condition are affected by glucose and should be considered for modelling a system to achieve the possibility of non-invasive blood glucose measurement with ECG.

背景与目标： 背景：在全球范围内，在过去的三十年中，糖尿病（糖尿病）的病例有所增加，被记录为主要的死亡原因之一。这种流行病是人体无法调节血糖从而导致异常高血糖的一种新陈代谢疾病。遗传病在确定人对疾病的易感性方面起着重要作用，久坐的生活方式和不健康的饮食是支持当前全球流行的行为。糖尿病引起的并发症包括视力丧失，周围神经病变，心血管并发症等。这种情况的受害者需要不断地监测血液中的血糖，这要通过刺破手指来完成。该过程是痛苦的，不便的并且可能导致疾病感染。因此，重要的是找到一种非侵入性地测量血糖的方法，以最小化或消除常规血糖监测中遇到的缺点。
方法：本文在连续捕获心电图（ECG）数据的同时对16名参与者进行了两个实验。在第一个实验中，要求参与者食用75微克无水葡萄糖溶液（口服葡萄糖耐量试验），而在第二个实验中，不服用葡萄糖溶液。我们探索了从心电图信号得出的HRV，HR，R-H，P-H，PRQ，QRS，QT，QTC和ST段的统计和频谱分析，以研究应考虑哪些段以实现无创血糖监测。在统计分析中，我们使用箱线图技术检查了数据的模式以揭示数据统计特性的变化。功率谱密度估计用于频谱分析，以显示数据的频率分布。
结果：在第一个四分位数，中位数和均值属性的参与者中，HRV区段的减少模式统计得分为81％，HR区段的增加模式统计得分相同。尽管ST段在第三个四分位数中减少模式的统计得分为81％，但QT段中位数在增加模式中的得分为81％。从总变化得分6中，ST，QT，PRQ，P-H，HR和HRV分别为4、5、4、5和6。对于频谱分析，HRV和HR得分分别为81和75％。 ST，QT和PRQ分别占75％，62％和68％。
结论：获得的结果表明，正常，健康条件下的HR，HRV，PRQ，QT和ST段受葡萄糖影响，应考虑为系统建模以实现使用ECG进行无创血糖测量的可能性。

BACKGROUND & AIMS: AIM:To compare electrocardiography (ECG)-gated computed tomography angiography (CTA) with ECG-gated magnetic resonance angiography (MRA) for assessment of the left atrium (LA) and pulmonary veins (PVs). MATERIAL AND METHODS:Twenty-nine consecutive patients who underwent both cardiac CTA and MRA were evaluated. Contrast-enhanced CTA was performed with prospective ECG-gating using a 320 detector row CT system. Contrast-enhanced MRA was performed with prospective ECG-gating using a 1.5 T MRI system equipped with a 32 channel cardiac coil. MRA was acquired during free-breathing with a navigator-gated inversion-recovery prepared steady-state free precession sequence. Two readers independently assessed the CTA and MRA images for vascular definition of the PVs (from 0, not visualized, to 4, excellent definition) and ostial PV diameters. Variants of LA anatomy were assessed in consensus. RESULTS:CTA was successfully performed in all patients with a mean radiation exposure of 5.1 ± 2.2 mSv. MRA was successfully performed in 27 of 29 patients (93 %). Visual definition of PVs was rated significantly higher on CTA compared to MRA (p < 0.0001; reader 1: excellent/good ratings of CTA versus MRA: 100% versus 86%; reader 2: excellent/good ratings of CTA versus MRA: 99% versus 89%). Assessment of ostial PV diameters showed good correlation between CTA and MRA (reader 1: Pearson r = 0.91; reader 2: Pearson r = 0.82). Moreover, agreement between both imaging methods for evaluation of variants of LA anatomy was high (agreement rate of 95% (95% CI: 92-99%). CONCLUSION:ECG-gated CTA provides higher image quality compared to ECG-gated MRA. Nevertheless, both CTA and MRA provided similar information of LA anatomy and ostial PV diameters.

背景与目标： 目的：比较心电图（ECG）门控计算机断层扫描血管造影（CTA）与心电图门控磁共振血管造影（MRA），以评估左心房（LA）和肺静脉（PVs）。
材料与方法：对连续接受心脏CTA和MRA的29例患者进行了评估。使用320排探测器CT系统，通过预期的ECG门控进行对比增强的CTA。使用配备32通道心脏线圈的1.5 T MRI系统，对前瞻性ECG门控进行对比增强的MRA。 MRA是在自由呼吸过程中通过导航器选通的反向恢复准备的稳态自由进动序列获得的。两名读者分别评估了CTA和MRA图像的PV的血管定义（从0，未可视化，到4，极佳的清晰度）和口腔PV直径。对LA解剖结构的变异进行了共识性评估。
结果：所有患者均成功进行了CTA，平均放射线暴露为5.1±2.2 mSv。在29例患者中有27例（93％）成功进行了MRA。与MRA相比，PV的视觉清晰度在CTA上的评级显着更高（p <0.0001；阅读器1：CTA与MRA的优异/良好评级：100％对86％；阅读器2：CTA与MRA的优异/良好评级：99％则为89％）。眼部PV直径的评估显示CTA与MRA之间具有良好的相关性（阅读器1：Pearson r = 0.91；阅读器2：Pearson r = 0.82）。此外，两种成像方法之间用于评估LA解剖结构变异的一致性很高（一致率为95％（95％CI：92-99％））。
结论：与ECG门控MRA相比，ECG门控CTA可提供更高的图像质量。尽管如此，CTA和MRA均提供了类似的LA解剖结构和小室PV直径信息。

BACKGROUND & AIMS: :Circumscribed areas of injured myocardium which lead to late ventricular depolarization represent the pathologic-anatomic substrate for reentry mechanisms potentially capable of propagating ventricular tachycardia at the ventricular level. If the myocardial area from which delayed ventricular depolarization and, consequently, late potentials eminate, exceeds a critical minimal size, documentation of such signals can not only be achieved with direct endocardial mapping or catheter mapping but also by means of special high-resolution ECG techniques from the body surface. Since high amplification of the conventional ECG results in registration of noise signals in amplitude of up to 50 microV, late potentials with their amplitudes at the body surface ranging from 5 to a maximum of 20 microV, can only be discriminated after substantial enhancement of the signal-to-noise ratio. The noise arises from no less than three sources: physiologic noise, for example, from muscle activity; electronic noise from amplifiers and background noise of 50 or 60 Hz, respectively. To improve the signal-to-noise ratio, currently three methods are employed: sequential or temporal signal averaging, spatial signal averaging and fast Fourier transformation analysis of the frequency spectrum of the highly-amplified ECG. Temporal signal averaging has the purpose of smoothing randomly-occurring background noise and, at a specified point in time of the ECG cycle, to sum the signal incurred. The effectivity of this technique, however, is subject to certain conditions: the signal to be registered and the background noise must be independent from each other, the noise must be stationary and show normal random distribution, the signal of interest must be periodic and/or coupled with a fixed interval to a point in the ECG cycle which can be used as a trigger. The quality of the averaged signal is dependent on trigger stability. There are three approaches to trigger processing: voltage threshold determination, slope detection and the pattern matching technique, the accuracy, reliability and time-consumption of which increases in the order listed. A trigger stability of +/- 0.5 ms is necessary to detect ventricular late potentials with sufficient sensitivity and without meaningful deformation or attenuation of their form and temporal extent. Intercurrently, a number of commercially-acquirable signal averaging computers have been made available which differ with respect to registration and analysis.(ABSTRACT TRUNCATED AT 400 WORDS)

背景与目标： ：导致晚期心室去极化的受伤心肌的边界区域代表折返机制的病理解剖学底物，其可能能够在心室水平传播心室性心动过速。如果延迟心室去极化并因此消除晚期电位的心肌面积超过了临界最小尺寸，则不仅可以通过直接心内膜标测或导管标测，而且可以通过特殊的高分辨率心电图技术来实现此类信号的记录从身体表面。由于常规ECG的高放大倍数导致噪声信号的振幅高达50 microV，因此只有在大幅增强信号后才能识别出体表振幅范围从5到最大20 microV的晚期电势。噪声比。噪声来自至少三个来源：生理噪声，例如，来自肌肉活动；以及放大器的电子噪声和50或60 Hz的背景噪声。为了提高信噪比，目前采用三种方法：顺序或时间信号平均，空间信号平均以及对高度放大的ECG频谱的快速傅里叶变换分析。时间信号平均的目的是平滑随机发生的背景噪声，并在ECG周期的指定时间点对产生的信号求和。但是，此技术的有效性受某些条件的限制：要记录的信号和背景噪声必须彼此独立，噪声必须稳定且显示正态随机分布，感兴趣的信号必须具有周期性和/或以固定间隔与ECG周期中的某个点配合使用，可以用作触发条件。平均信号的质量取决于触发的稳定性。共有三种触发处理方法：电压阈值确定，斜率检测和模式匹配技术，其准确性，可靠性和时间消耗按列出的顺序增加。 0.5 ms的触发稳定性对于以足够的灵敏度检测心室晚期电位，而不会对其形式和时间范围造成有意义的变形或衰减是必要的。同时，已经提供了许多在商业上可以买到的信号平均计算机，它们在注册和分析方面有所不同。（摘要截断为400字）

BACKGROUND & AIMS: Background:Cardiovascular disease is the leading cause of morbidity and mortality in developed countries. Many patients do not experience symptoms before a first major cardiovascular event. Resting electrocardiogram (ECG) may help identify asymptomatic individuals with a high risk of cardiovascular disease. Objective:We sought to determine the prevalence of ECG abnormalities in an apparently symptom-free adult population within a prospective registry. Methods:The registry consisted of 4739 consecutive apparently healthy individuals [age 62.8 ± 6.2 (SD) years; 54% female], referred by their General Practitioners between 2009 and 2013. Patient demographics, and clinical data were obtained, alongside blood tests and a resting ECG. Results:ECG abnormalities were present in 1509 (31.8%) subjects and were commoner with increasing age (F = 0.161, p = 0.01), systolic (F = 0.134, p = 0.01) and diastolic (F = 0.44, p = 0.01) blood pressure and waist circumference (F = 0.53, p = 0.01). Left ventricular hypertrophy (LVH) was the most common abnormality (n = 281) and was positively associated with systolic (F = 0.12, p = 0.01) and diastolic blood pressure (F = 0.99, p = 0.01) and male gender (X2 = 60.5, p < 0.01). All ECG abnormalities (except for LVH) were associated with an increasing age, while right bundle branch block (F = 0.041, p = 0.01) and atrial fibrillation (n = 29; F = 0.036, p = 0.05) were associated with the presence of diabetes mellitus (n = 211). Only left bundle branch block (n = 50) was associated with angina (F = 0.05, p = 0.01). Conclusions:Unrecognized cardiac abnormalities are common in middle-aged men and women with no overt symptoms. ECG offers the potential to identify these abnormalities and provide earlier intervention and treatment, and possibly improve cardiovascular outcome.

背景与目标： 背景：心血管疾病是发达国家发病率和死亡率的主要原因。许多患者在第一次重大心血管事件发生之前没有出现症状。静息心电图（ECG）可能有助于识别具有心血管疾病高风险的无症状个体。
目的：我们试图在前瞻性登记系统中确定明显无症状的成年人群中心电图异常的患病率。
方法：登记册由4739名连续的表观健康的个体组成[年龄62.8±6.2（SD）岁； 54％的女性]，由其全科医生在2009年至2013年之间转诊。获得了患者的人口统计资料和临床数据，以及血液检查和静息的心电图。
结果：1509名受试者（31.8％）存在心电图异常，并且随着年龄的增长（F = 0.161，p = 0.01），收缩期（F = 0.134，p = 0.01）和舒张期（F = 0.44，p = 0.01）而普遍存在。血压和腰围（F = 0.53，p = 0.01）。左心室肥大（LVH）是最常见的异常（n = 281），与收缩压（F = 0.12，p = 0.01）和舒张压（F = 0.99，p = 0.01）和男性（X2 = 60.5，p <0.01）。所有的ECG异常（LVH除外）都与年龄增长有关，而右束支传导阻滞（F = 0.041，p = 0.01）和房颤（n = 29; F = 0.036，p = 0.05）与存在有关。糖尿病（n = 211）。仅左束支传导阻滞（n = 50）与心绞痛相关（F = 0.05，p = 0.01）。
结论：没有明显症状的中年男性和女性普遍存在无法识别的心脏异常。心电图有可能发现这些异常现象并提供更早的干预和治疗，并可能改善心血管疾病的预后。

BACKGROUND & AIMS: :The type 1 ST-segment elevation is diagnostic for Brugada syndrome (BS) and its presence may sometimes be associated with a high risk of arrhythmic events. The type 1 ECG is also known to be unmasked by administration of sodium-channel blockers in equivocal or suspected cases of BS, and the drug-challenge test is frequently used in the diagnostic approach. In large cohort studies the spontaneous appearance of the type 1 ECG with symptoms of aborted sudden death or unexplained syncope are indicative of a poor prognosis for patients with BS compared with not having clinical symptoms. Therefore, the spontaneous type 1 ECG appears to represent an important predictive sign for cardiac events. It is unknown, however, whether or not the drug-induced type 1 ECG is as useful as the spontaneous type 1 for predicting cardiac events in asymptomatic subjects showing non-type 1 ECG. Review of the literature for large cohort studies indicates that there is a low incidence of arrhythmic events in asymptomatic patients with either the spontaneous or drug-induced type 1 ECG compared with symptomatic subjects, and the drug-induced type 1 ECG in asymptomatic patients does not add to an increase in arrhythmic risk. Therefore, drug testing to unmask the type 1 ECG in asymptomatic patients with a non-type 1 BS ECG does not have an additional value for risk stratification of cardiac events, although it might be useful in symptomatic patients showing only the non-type 1 ECG.

背景与目标： ：1型ST段抬高可诊断为Brugada综合征（BS），有时其存在可能与心律不齐事件的高风险相关。还已知在模棱两可的或疑似的BS病例中通过给予钠通道阻滞剂可以掩盖1型ECG，并且在诊断方法中经常使用药物挑战试验。在大型队列研究中，伴有猝死或不明原因的晕厥症状的1型ECG的自发出现表明BS患者的预后较差，而没有临床症状。因此，自发的1型心电图似乎代表了心脏事件的重要预测指标。然而，未知药物诱发的1型心电图是否与自发1型心电图在预测无症状的非1型心电图受试者的心脏事件方面有用。大量队列研究的文献综述表明，与有症状的受试者相比，无症状的自发性或药物诱导型1型心电图患者的心律失常事件发生率低，而无症状的患者所致的1型心电图药物性心律失常事件的发生率不高。增加心律失常的风险。因此，对无症状的非1型BS心电图患者进行1型心电图检查的药物测试，对于心脏事件的危险分层没有附加价值，尽管它对于仅显示非1型心电图的有症状患者可能有用。

BACKGROUND & AIMS: :Beat-to-beat variability (BTBV) of the fetal heart rate (FHR) is considered an indication of the neural integrity and is an important prognostic indicator of fetal well-being. We report the initial evaluation of a recently developed abdominal fetal ECG (AFECG) mode of FHR monitoring using Adaptive Digital Filtering (ADF) to accurately obtain BTBV noninvasively. Five women in labor at term were monitored with the direct fetal scalp electrode (FSE) and simultaneously with the AFECG using ADF. A computer analysis of 3298 seconds (55 minutes) of data provided a one-to-one comparison of the R-R intervals. One analysis of the direct FSE data with a second simultaneous analysis from the same electrode, to serve as control, was compared with the noninvasive AFECG data. The study group has a standard deviation of only 1.50 bpm compared to 0.79 bpm for the control group. The AFECG method agrees with the direct FSE method within 1 bpm for 92.6% of the reported R-R intervals and within 2 bpm for 98.9% of the reported intervals. This new noninvasive AFECG technique with ADF provides a continuous record of instantaneous FHR and BTBV that may be relied upon to provide an accurate continuous clinical record. The reliability of the technique has yet to be determined over a wide range of subjects.

背景与目标： ：胎儿心率（FHR）的逐跳变化（BTBV）被认为是神经完整性的指标，并且是胎儿健康的重要预后指标。我们报告了使用自适应数字滤波（ADF）来无创准确地获得BTBV的FHR监测的最近开发的腹部胎儿ECG（AFECG）模式的初步评估。足月分娩的五名妇女使用直接胎儿头皮电极（FSE）进行监测，同时使用ADF使用AFECG进行监测。对3298秒（55分钟）的数据进行的计算机分析提供了R-R间隔的一对一比较。将直接FSE数据的一种分析和来自同一电极的第二种同时分析作为对照，与无创AFECG数据进行了比较。与对照组的0.79 bpm相比，研究组的标准偏差仅为1.50 bpm。 AFECG方法与直接FSE方法相一致，在报告的R-R间隔的1 bpm内和报告的间隔的98.9％的2 bpm内。这项采用ADF的新型非侵入性AFECG技术可提供瞬时FHR和BTBV的连续记录，可依靠该记录来提供准确的连续临床记录。该技术的可靠性尚未在广泛的主题中确定。

BACKGROUND & AIMS: OBJECTIVE:High reproducibility on coronary artery calcium (CAC) scoring is a key requirement in monitoring the progression of coronary atherosclerosis. Retrospective ECG-gated helical CT has been shown to be superior to prospective gating helical CT in the reproducibility of CAC measurements. However, it brings with it a high level of radiation exposure. The purpose of this study was to compare low- and standard-dose protocols in the variability of CAC scores and in image quality, thereby assessing the feasibility of low-dose retrospective ECG-gated helical CT in CAC measurements. SUBJECTS AND METHODS:Eighty-six patients with CAC were scanned using a tube current setting of 100 mA once and then a tube current setting equivalent to the patient's body weight twice. CAC scores (Agatston and volume) and interscan variability were evaluated. The mean and SD of the CT attenuation values in regions of interest in the aorta were measured, and the value (mean + 2 x SD) was obtained. RESULTS:A high correlation of log(10) (Agatston score + 1) was observed between sequential helical CT scans (r = 0.998). The variability in CAC measurements ranged from 11% to 12% for both the Agatston and volume scores. With the tube current equivalent to body weight, the value (mean + 2 x SD) did not exceed a CT attenuation value of 130 H. CONCLUSION:Low-dose retrospective ECG-gated helical CT-yielding low variability and achieving the level of image quality needed to measure CAC-can be used to monitor patients with coronary atherosclerosis.

背景与目标： 目的：冠状动脉钙（CAC）评分的高可重复性是监测冠状动脉粥样硬化进展的关键要求。回顾性ECG门控螺旋CT在CAC测量的可重复性方面优于预期门控螺旋CT。然而，它带来了高水平的辐射暴露。这项研究的目的是比较低剂量和标准剂量方案在CAC评分的变异性和图像质量方面的差异，从而评估低剂量回顾性ECG门控螺旋CT在CAC测量中的可行性。
研究对象和方法：对86例CAC患者进行了一次扫描，一次使用100 mA的管电流设置，然后两次使用等于患者体重的管电流设置进行扫描。评估了CAC评分（Agatston和体积）和扫描间变异性。测量主动脉中感兴趣区域的CT衰减值的平均值和SD，并获得该值（平均值2 x SD）。
结果：连续螺旋CT扫描之间观察到log（10）（Agatston评分1）的高度相关性（r = 0.998）。对于Agatston和体积得分，CAC测量的变异性范围从11％到12％。在管电流等于体重的情况下，该值（平均值2 x SD）不超过130 H的CT衰减值。
结论：低剂量回顾性心电门控螺旋CT产生的低变异性和达到测量CAC所需的图像质量水平可用于监测冠状动脉粥样硬化患者。

BACKGROUND & AIMS: BACKGROUND:Twelve-lead ECG represents the most common diagnostic tool in clinical cardiology and allows an immediate screening of left ventricular hypertrophy (LVH), but current criteria might have poor clinical usefulness in everyday clinical practice due to lack of sensitivity. METHODS:The current study aims to review and compare the clinical performance of known ECG criteria of LVH in a real-life setting; 2134 patients had ECG and echocardiographic exams performed during the same hospitalization. All traces were retrospectively analysed, and the amplitudes of the waves were manually measured. Transthoracic echocardiography was considered as the gold standard to assess LVH. RESULTS:LVH had a prevalence of 58%. Considering the diagnostic performance of ECG criteria for LVH, the Cornell voltage carried the best area under the receiver operating characteristic curve (0.678), while RaVF (R wave in aVF lead) had the poorer result (0.440). The R5/R6 criterion had the best sensitivity (60%), but with the worst specificity (37.4%). The 'Q or S aVR' had the best specificity (99.9%) but lacks sensitivity (0.80%). The Peguero Lo Presti criterion had a sensitivity of 42.3% and a specificity of 75.8%. The Cornell voltage and the Cornell product had similar area under the receiver operating characteristic curve values which were found to be significantly greater compared with other criteria. CONCLUSION:Current ECG criteria of LVH have low sensitivity despite an acceptable specificity. Among these, Cornell voltage and Cornell product criteria were equally found to have a more accurate diagnostic performance compared with other criteria. To overcome the intrinsic limitations of the current ECG LVH criteria, a new paradigm in the analysis of electrocardiographic data might be necessary.

背景与目标： 背景：十二导联心电图代表临床心脏病学中最常见的诊断工具，可以立即筛查左心室肥大（LVH），但由于缺乏敏感性，目前的标准在日常临床实践中可能具有较差的临床实用性。
方法：本研究旨在回顾和比较已知LVG ECG标准在现实生活中的临床表现。在同一次住院期间对2134例患者进行了心电图检查和超声心动图检查。回顾性分析所有迹线，并手动测量波幅。经胸超声心动图被认为是评估LVH的金标准。
结果：LVH的患病率为58％。考虑到ECG标准对LVH的诊断性能，康奈尔电压在接收器工作特性曲线下的面积最大（0.678），而RaVF（aVF导线中的R波）的结果较差（0.440）。 R5 / R6标准的灵敏度最高（60％），但特异性最低（37.4％）。 “ Q或S aVR”具有最高的特异性（99.9％），但缺乏敏感性（0.80％）。 Peguero Lo Presti标准的灵敏度为42.3％，特异性为75.8％。在接收器工作特性曲线值下，康奈尔电压和康奈尔产品具有相似的面积，发现与其他标准相比，该面积明显更大。
结论：尽管有可接受的特异性，目前LVH的ECG标准仍具有较低的敏感性。其中，与其他标准相比，康奈尔电压和康奈尔产品标准同样具有更准确的诊断性能。为了克服当前ECG LVH标准的固有局限性，在心电图数据分析中可能需要一种新的范例。

BACKGROUND & AIMS: :In this paper a new version, more immune to noise, of the nonlinear projective filtering is presented. The method employs an algorithm of robust principal component analysis to signal subspaces construction and as a result it achieves high performance in real electromyographic noise environment. Two aspects of the method's action are investigated: its ability to suppress noise and its influence on the precision of the QT interval measurement. Then the method influence on evaluation of the beat-to-beat variability of the repolarization duration is presented. A comparison to the previous versions of the nonlinear projective filtering and to the classical linear one is carried out.

背景与目标： ：在本文中，提出了一个新版本的非线性射影滤波，对噪声更具免疫力。该方法采用鲁棒的主成分分析算法来构造信号子空间，因此在真实的肌电图噪声环境中具有很高的性能。研究了该方法的作用的两个方面：其抑制噪声的能力及其对QT间隔测量精度的影响。然后介绍了该方法对复极化持续时间的逐拍变异性评估的影响。与以前的非线性射影滤波和经典的线性射影滤波进行了比较。