急性心肌缺血时高频心电图时域频域分析的实验研究

结扎家兔冠状动脉的不同部位，用高频心和时域频域法观察中高频成分、甚高频成分的变化。结果表明缺血面积小地３５％时，中高频面分、甚高频分随缺血范围的增大而增加；若缺血面积大于３５％时，中高频成分、甚高频成分减少。     

无明确原因低电压患者的频域心电图观察

无明确原因低电压患者的频域心电图观察徐学文（解放军９１医院特诊科兖州２７２０００）关键词心电图，低电压心电信号，频域分析常规心电图上的低电压有多种原因，在正常人中偶可见到（约占１％），仅是“电压过低”并不一定表示有器质性心脏病变，也不足以诊断为心电图...     

运动性QRS波高频电压改变及临床意义

本文探讨运动性ＱＲＳ波高频电压改变及临床意义。３６例心肌梗死，４５例心绞痛，５２例胸闷，５７例康复者及４８例正常人，共２３８例，分别于运动前后进行了常规心电图和高频心电图检测。运动后，常规心电图有改变者很少，而高频心电图每例都有明显改变；ＱＲＳ波高频电压，在冠心病患者中是下降的，在正常人中是上升的，两者差异非常显著（Ｐ＜０．０１）。这表明，运动性ＱＲＳ波高频电压改变，可作为心肌是否缺血的参考指标，其敏感性高达１００％，特异性可达８７．５％。     

HFECG 对高血压心脏病的诊断价值

ＨＦＥＣＧ对高血压心脏病的诊断价值苏晓飞葛本贤杨国柱（南京市雨花医院内科南京２１００１２）关键词心脏病高血压心电描记术，高频高频心电图（ＨＦＥＣＧ）应用于临床已近１０年。当心肌表现为缺血、坏死、纤维化，心肌去极化出现先后、快慢，心室传导过程出现障碍时...     

心脏ECT展开图评价异舒吉和硝酸甘油抗心肌缺血作用

目的　评价比较 ２ 种药物异舒吉和硝酸甘油抗心肌缺血作用。方法　利用９９ ｍ Ｔｃ Ｍ Ｉ Ｂ Ｉ灌注断层显象展开图比较药物治疗前后左室缺血面积的改善情况，用面积的改善反映药物的抗心肌缺血作用。结果　异舒吉治疗前后缺血心肌面积分别为３２５９７± ６２９５ ｃｍ ２ 、２８６７３ ±３１３１ ｃｍ ２， 治 疗前 后缺血 面积 与左 室面 积的 百分 比分别 为 １７２５４％ ±５６１４％ 、１５４０１％ ±２７８０％ ；硝酸甘油治疗前后缺血面积分别为 ３２１２６ ±５４７８ ｃｍ ２ 、２９７０２±２９８２ ｃｍ ２， 缺血面积与左室面积 的百分比分别为１６９８９％ ±５６１４％ 、１５９２３％ ±２７８０％ （ Ｐ＜ ００５）。治疗前后，异舒吉组的缺血面积改善程度与硝酸甘油组相比无差异（ Ｐ ＞００５）。结论　异舒吉和硝酸甘油均有抗心肌缺血作用，临床医生需要注意“成本效果分析     

运动性QRS波高频电压改变及临床意义

本文探讨运动性ＱＲＳ波高频电压改变及临床意义，３６例心肌梗死，４５例心绞痛，５２例胸闷，５７例康复者及４８例正常人，共２３８例，分别于于运动前后进行了常规心电图和高频心电图检测。运动后，常规心电图有改变者很少，而高频心电图每例都有明显改变；ＱＲＳ波高频电压，在冠心病患者中是下降的，在正常中是上升的，两者差异非常显著。这表明，运动性ＱＲＳ波高频电压改变，可作为心肌是否缺血的参考指标，其敏感性高达１０     

急性心肌梗死患者溶栓对心率变异性的影响

选取急性心肌梗死（ＡＭＩ）患者３１例，并设正常对照组。采用时域法和频域法研究ＡＭＩ溶栓治疗后心率变异性（ＨＲＶ）的改变。其结果显示:在ＡＭＩ再通组，其ＳＤＮＮ为１０８．１４±２８．４０ｍｓ，高于未通组的６２．６７±２６．１２ｍｓ（Ｐ＜０．０１）但低于对照组的１２８．４７±３５．６１ｍｓ（Ｐ＜０．０５）；其高频面积为２８４．８２±２７６．４５，大于未通组的（１３５．６８±１１７．８２ｂｐｍ２／Ｈｚ，Ｐ＜０．０５）但小于对照组的（６９４．３５±５４０．１１ｂｐｍ２／Ｈｚ，Ｐ＜０．０１）；其低频面积／高频面积为０．９３±０．７１，小于未通组的１．７４±１．０７（Ｐ＜０．０５），但大于对照组的０．５３±０．６１（Ｐ＜０．０１）；其低频面积虽大于未通组和小于对照组，但无统计学意义。本结果表明，ＡＭＩ后ＨＲＶ变小，其迷走神经活性下降，交感神经作用相对增强；溶栓再通后的ＨＲＶ增大，其迷走神经兴奋性增高，交感神经作用减弱。故成功的溶栓治疗对改善ＡＭＩ后自主神经系统功能失衡和减少由此引起的致命性心律失常等事件的发生有积极意义     

体感诱发电位的高频振荡成分在皮层下动脉硬化性白质病变的观察

目的探讨体感诱发电位(SEPs)高频振荡(HFQs)成分在皮层下动脉硬化性白质病变的异常表现，及其HT能的病理生理基础。方法在一组诊断明确的皮层下动脉硬化性白质病变的病人共70例中，进行正中神经体感诱发电位和高频振荡成分的检测，比较常规体感诱发电位成分和高频振荡成分的异常率和异常模式。结果常规体感诱发电位成分的异常率为8．6％，HFOs的异常率为45．7％；两者的异常模式有：两者同时异常4．3％，常规体感诱发电位成分正常，HFOs异常41．4％，常规体感诱发电位成分异常，HFOs正常4．3％。结论体感诱发电位高频成分和常规成分的异常反映感觉传入过程中不同的紊乱模式，高频成分对皮层下的神经纤维轻度脱髓鞘更为敏感，对常规体感诱发电位是一个有益的扩充指标。     

显性房室旁道射频消融术后QRS波群高频成分的？…

探讨房室旁道电位的电物理特性，同时借助房室旁道这一除极顺序异常的天然模型，印证心室激动传导异常产生高频成分这一机制，选择显性室旁道伴房室折返性心动过速患者４０例，采用信号平均技术及多采样率线性小波转换技术，对射频消融前，后体表心电图窦性心律时ＱＲＳ波群全程及起始部４０ｍｓ进行三维频谱分析，观察高频能量（Ｅ１）甚高频能量（Ｅ２）频谱的最高上限频率（Ｆｍａｘ）及ＱＲＳ时限（ＱＲＳＩ）等参数的变化，结果     

溶血磷脂胆碱在缺血性心律失常中的作用

用台氏液加溶血磷脂胆碱（ＬＰＣ）３×１０－４ｍｏｌ／Ｌ灌流离体绵羊心室小梁肌，其０期去极化最大速率（Ｖｍａｘ）、静息电位（ＲＰ）、动作电位幅值（ＡＰＡ）、动作电位复极达ＡＰＡ５０％和ＡＰＡ９０％的时程（ＡＰＤ５０，ＡＰＤ９０）分别下降３９．８％，１０．４％，１４．５％，２１．３％和１４．８％（ｎ＝１２，Ｐ＜０．０１）；用“模拟缺血溶液”和ＬＰＣ３×１０－４ｍｏｌ／Ｌ灌流，其Ｖｍａｘ，ＲＰ，ＡＰＡ，ＡＰＤ５０，ＡＰＤ９０分别下降７８．０％，２２．７％，２６．０％，３５．４％和２１．０％。实验中对“模拟缺血溶液”中各种成分对ＬＰＣ效应的影响进行分析，发现其主要因素是酸中毒。结果表明:ＬＰＣ是心肌缺血中心律失常的重要因素之一，缺血诱导的酸中毒更加重了ＬＰＣ对心肌细胞的毒性作用     

Characterisation of very low frequency oscillations in laser Doppler perfusion signals with a singular spectrum analysis

Laser Doppler (LD) perfusion signals consist of a number of superimposed frequencies that span a wide range. Singular spectrum analysis (SSA) was used to characterise the very low frequency (VLF) components as this method can extract frequencies of interest from the time domain. Its utility is demonstrated on a sex health clinical data set where the focus was on VLF oscillations. A significant change in this frequency range can be measured with SSA when the subject is undergoing erotic stimulation.     

超声多探头检查在新生儿颅脑疾病诊断中的应用

目的研究超声低频探头和低频探头联合高频探头检查在新生儿颅脑疾病诊断中的准确率和敏感性。 方法选取河源市妇幼保健院自2017年1月至2018年12月收治的有颅脑疾病高危因素(早产、低体质量、多胎妊娠、出生过程有缺氧窒息及产时感染)的新生儿90例作为研究对象。采用随机数字表法将所有新生儿平均分为2组，研究组（45例）给予低频探头联合高频探头进行探查，对照组（45例）仅给予低频探头进行探查。结合CT检查结果和临床治疗，比较2种检测方法的准确率和敏感性。 结果研究组检测新生儿缺氧缺血性脑病、脑室内出血和室管膜下出血诊断准确率分别为87.5%、100%、100%，高于相应对照组（15.38%、12.5%、0%），差异有统计学意义（P<0.05）；研究组和对照组检测脑实质内出血和脑积水的诊断准确率分别为87.5%、100%以及42.85%、66.67%，差异无统计学意义（P>0.05）。研究组检测新生儿颅脑疾病的效率为82.22%，高于对照组（22.22%），差异具有统计学意义（P<0.05）。 结论使用超声低频探头联合高频探头的方法提高了缺氧缺血性脑病、脑室内出血、室管膜下出血等新生儿颅脑疾病诊断的准确率，在诊断新生儿脑实质内出血和脑积水的准确率没有差异，且对颅脑疾病诊断的敏感性较高，因此具有较为重要的临床意义。     

Quantifying QRS changes during myocardial ischemia: Insights from high frequency electrocardiography

Over four decades of high frequency electrocardiography research have provided a body of knowledge about QRS changes during myocardial ischemia, and the techniques to measure and quantify them. High-frequency QRS (HFQRS) components, being closely related to the pattern of ventricular depolarization, carry valuable clinical information. Changes in HFQRS amplitude and morphology have been shown to be sensitive diagnostic markers of myocardial ischemia, often superior to measures of ST-T segment changes. Clinical studies in patients undergoing exercise testing have consistently demonstrated the incremental diagnostic value of HFQRS analysis in detection of demand ischemia. In 6 studies that evaluated the HyperQ™ technology, the average sensitivity and specificity of HFQRS analysis were 75% ± 6% and 80% ± 6%, respectively, compared to average sensitivity 48% ± 16% and average specificity 70% ± 15% of ST segment analysis. In patients with acute supply ischemia, recent studies characterized and quantified the ischemic HFQRS patterns. HFQRS morphology index was found to be higher in patients with acute coronary syndrome (ACS), compared to non-ischemic, with good sensitivity in patients without ST elevation. These research findings may be translated into commercially-available ECG systems and be used in clinical practice for improved diagnosis and monitoring of myocardial ischemia.     

高、低频超声联合应用在老年人急性阑尾炎诊断中的价值

目的探讨高、低频超声联合应用在老年急性阑尾炎患者中的诊断价值。方法对2013年在我院急救中心就诊的62名老年急性阑尾炎患者,先用低频超声检查,后行高频超声检查,确定阑尾位置、走形、回声及血流情况,做出急性阑尾炎的超声诊断。结果 62名老年急性阑尾炎患者中,低、高频联合超声诊断检出58例,漏诊3例,误诊1例,与术后病理诊断符合率为93.5%。结论低频及高频超声联合检查急性阑尾炎分别从整体和局部入手,起到互补的作用,从而提高阑尾炎的显示率及诊断的准确性。     

Ultrasonic characterization of porcine liver tissue at frequency between 25 to 55 MHz

AIM: To study the relation between acoustic parameters and histological structure of biological tissue and to provide the basis for high-resolution image of biological tissues and quantitative ultrasonic diagnosis of liver disease. METHODS: Ultrasonic imaging and tissue characterization of four normal porcine liver and five cirrhotic liver tissue samples were performed using a high frequency imaging system. RESULTS: The acoustic parameters of cirrhotic liver tissue were larger than those of normal liver tissue. The sound velocity was 1577 m/s in normal liver tissue and 1631 m/s in cirrhotic liver tissue. At 35 MHz, the attenuation coefficient was 3.0 dB/mm in normal liver tissue and 4.1 dB/mm in cirrhotic liver tissue. The backscatter coefficient was 0.00431 dB/Srmm in cirrhotic liver tissue and 0.00303 dB/Srmm in normal liver tissue. The backscatter coefficient increased with the frequency. The high frequency images coincided with their histological features. CONCLUSION: The acoustic parameters, especially the sound backscatter coefficient, are sensitive to the changes of liver tissues and can be used to differentiate between the normal and pathological liver tissues. High frequency image system is a useful device for high-resolution image and tissue characterization.     

氩气刀联合高频电刀及冷冻刀治疗气道狭窄的临床疗效

目的观察电子支气管镜下氩气刀联合高频电刀及冷冻刀治疗良恶性肿瘤所致气道狭窄的临床疗效。方法对33例良恶性肿瘤导致气道阻塞患者,经电子支气管镜下进行氩气刀、高频电刀及冷冻刀治疗,观察疗效和并发症的发生率。结果 33例患者共进行63次治疗,近期完全有效10例(30.3%),部分有效9例(27.3%),轻度有效12例(36.4%),无效2例(6.0%),33例患者中,术后12例出现痰血,6例出现38.0℃以下低热,无气胸、纵隔气肿、大咯血等严重并发症。结论支气管镜下氩气刀联合高频电刀及冷冻刀治疗良恶性肿瘤引起的气道阻塞疗效显著,对良性肿瘤避免了开胸手术,可达到临床根治;对恶性肿瘤疗效直接,是非常有效的姑息治疗手段。     

Carotid intima-media thickness measurements are not affected by the ultrasound frequency

Objective: Carotid intima‐media thickness (IMT) is a B‐mode ultrasound measure of subclinical atherosclerosis predictive of future cardiovascular risk. Carotid IMT measurements were historically obtained at an ultrasound frequency of 8 MHz or lower, but it is unknown whether measurements obtained at higher frequencies using newer, more advanced ultrasound technology allow for valid comparison to the older general population databases that are commonly used for the interpretation of carotid IMT results. Methods: Carotid IMT studies were conducted in 35 consecutive patients at standard (8 MHz) and high (14 MHz) frequencies and measurements were performed by two independent expert readers. Systematic bias was assessed by using the paired t‐test and agreement was analyzed with the Bland–Altman method. Results: The sample mean carotid IMT obtained at 14 MHz was 0.006 mm lower than that obtained at 8 MHz. The 95% confidence interval (CI) for the mean difference between frequencies indicated that the population mean for 14 MHz is unlikely to be more than 0.02 mm lower than for 8 MHz (95% CI –0.017 to 0.004). The 95% reference range for the difference between the two transducer frequencies indicated that the thickness obtained at 14 MHz was within 0.05 mm of that obtained at 8 MHz for 95% of subjects. Conclusions: Carotid IMT measurements obtained at higher transducer frequencies are similar to those obtained at standard frequency. This finding has important clinical implications because it validates comparison of carotid IMT measurements obtained with newer, more advanced ultrasound technology with the landmark reference carotid IMT studies commonly used for interpretation of carotid IMT results. (Echocardiography 2012;29:354‐357)     

Technical considerations for dominant frequency analysis

Introduction : Dominant frequency (DF) analysis of atrial electrograms has been used to characterize atrial fibrillation (AF). The aim of this study was to explore technical issues that may affect the estimation of local activation rate during AF using DF analysis.
Methods and Results: Epicardial atrial electrograms recorded during AF from 10 dogs were used to evaluate the effects of unipolar versus bipolar recordings, bipolar electrode spacing, postrecording processing, far field ventricular depolarizations, ventricular template subtraction, and signal duration on DF analysis. Simulated electrograms were used to evaluate the effect of far field ventricular depolarizations and signal-to-noise ratio. DFs were compared with activation rates obtained by manual marking and the reproducibility of the DFs was evaluated. Bipolar electrograms were found to be preferable to unipolar electrograms. Preprocessing was a necessary step for bipolar signals, but also aided analysis of unipolar recordings. Ventricular far field depolarizations significantly affected DFs. Ventricular template subtraction helped DF analysis in signals with both minimal and significant ventricular components. A recording duration above 2 seconds was required for reliable DF measurements. Signal-to-noise ratios below 13 dB could also affect DF, particularly for signals with significant amplitude and frequency variation.
Conclusions: Various factors affect DF analysis. Proper interpretation of DF analysis requires careful evaluation of the AF signals and robust processing techniques.     

缺血性脑血管病患者脑动脉狭窄的分布及特征

目的　探讨动脉粥样硬化性缺血性脑血管病患者脑动脉狭窄的分布特征。方法　选择连续行主动脉弓 +全脑血管造影检查的成年缺血性脑血管病患者 196例 ,将其中 171例存在脑动脉狭窄的患者按年龄分为青年组 (18～4 4岁 )、中年组 (45～ 5 9岁 )及老年组 (≥ 6 0岁 ) ,分析脑动脉狭窄随年龄变化的分布规律。结果　 171例脑动脉狭窄的患者中颅内动脉狭窄的发生率 (80 .7% )明显高于颅外动脉 (5 6 .1% )。青年组单纯颅内动脉狭窄的比例较高 ,主要发生在大脑中动脉。中年组及老年组颅内、外动脉狭窄并存的比例较高。颅外动脉病变数目随年龄不断增加(P <0 .0 0 1)。结论　动脉粥样硬化性缺血性脑血管病患者颅内动脉狭窄的发生率高于颅外。脑动脉狭窄的分布有年龄特征性     

二尖瓣机械瓣置换术后凝血酶原时间-国际标准化比值检测频率与长期预后间关系的研究

目的探究凝血酶原时间-国际标准化比值（prothrombin time-international normalized ratio，PT-INR）检测频率与二尖瓣机械瓣置换术后长期预后之间的关系。 方法纳入2013年6月至2018年5月于南京医科大学第一附属医院接受二尖瓣机械瓣置换并康复出院的患者。电话问卷调查患者，根据PT-INR检测间隔是否超过1个月分为频繁检测组（≤1个月）和不频繁检测组（>1个月）。主要终点为全因死亡，次要终点为缺血性卒中及大出血，比较两组之间终点事件发生情况。 结果共收集249例患者信息，年龄（47.06±6.88）岁，其中男98例。共153例（61.4%，153/249）完成问卷者纳入分析。2013-2014年、2014-2015年、2015-2016年、2016-2017年、2017-2018年失访比例分别为76.1%，51.3%，26.7%，32.3%，15.8%；频繁检测比例分别为36.4%，36.8%，42.4%，35.7%，83.3%。随术后时间延长，失访和不频繁检测比例均显著增加（P<0.05）。80例（52.3%）纳入频繁检测组，73例（47.7%）纳入不频繁检测组。不频繁检测组共发生7例全因死亡，6例缺血性卒中，3例大出血；频繁检测组无死亡，1例缺血性卒中，2例大出血。频繁检测组累积死亡风险显著低于不频繁检测组（P=0.006）。 结论随术后时间延长，失访比例和不频繁检测PT-INR比例均显著增加，不频繁检测总体预后差于频繁检测。