Extraction of pacemaker and implantable cardioverter defibrillator leads

To determine the mechanisms by which human immunodeficiency virus type 1 (HIV-1) crosses the placenta into the fetal blood, 12 matched samples of serial maternal blood, term placentas, and infant blood obtained from a cohort of pregnant women in Cameroon identified as predominantly infected by subtype A viruses were studied. HIV-1 env sequences were detected by polymerase chain reaction (PCR) in both chorionic villi and enriched trophoblastic cells of all 12 placentas but at variable rates of detection. Heteroduplex mobility assay analysis showed the presence of multiple HIV-1 env quasispecies in sequential maternal peripheral blood mononuclear cell samples, but only a small number of env variants were found in chorionic villi and enriched trophoblastic cells. These data indicate that HIV-1 env sequences are always present in term placentas of seropositive women, contrasting with the low frequency at which infection is diagnosed by PCR in neonates with tat, gag, and env primers. Maternal HIV-1 variants appear to undergo a strong negative selection by different cell populations within the placental villi.     

Impedance of pacemaker leads: correlation of different methods

PURPOSE: Four children with an osteomyelitic process in the jaw bones while on cytotoxic chemotherapy were treated by radical surgery and antimicrobial chemotherapy. PATIENTS AND METHODS: Symptoms (local swelling and pain in the jaw, necrotic gingivitis, and spontaneous loss of teeth) appeared 3 weeks, 4 weeks, and 8 months after diagnosis of leukemia, and 8 days posttransplant in a patient with severe aplastic anemia. Three had the process in the mandible and one in the maxilla. Specific diagnoses of Aspergillus flavus, Saccharomyces cerevisiae, and Actinomyces species were obtained histologically from surgical samples. Treatment was radical surgery to remove all infected and necrotic tissue: removal of a substantial part of the mandible and loss of seven to eight permanent teeth in those with mandibular lesions. Actinomycosis was treated with penicillin for 2 years. The patients with fungal lesions received amphotericin B for 2, 5, and 6 months, with adjuvant itraconazole, fluconazole, or 5-fluorocytosine for 9-12 months. Anti-cancer chemotherapy was continued. RESULTS: All the bony lesions healed. The patient with acute myeloid leukemia died in relapse 1 year postdiagnosis; her aspergillus osteomyelitis had been inactive for 8 months. The other three patients are alive and well 1.9, 2.1, and 1.9 years after termination of antimicrobial therapy. CONCLUSIONS: We emphasize the necessity of specific diagnosis from appropriate surgical samples and conclude that in patients undergoing chemotherapy bony lesions caused by opportunistic microorganisms may be curable with aggressive surgery and prolonged medication.     

Percutaneous method for internal jugular venous introduction and retroclavicular placement of permanent endocardial leads

BACKGROUND: The aim of this study was to assess the familial aggregation of lipid levels in schoolchildren of Cuenca city, Spain. SUBJECTS AND METHODS: A cross sectional study was made including 307 both sexes schoolchildren 9-12 years old recruited in three schools of Cuenca city, and 346 of their parents. Sociodemographics variables, weight, height, body mass index, systolic blood pressure, diastolic blood pressure and fasting plasma total cholesterol, LDL-C, HDL-C and triglyceride concentrations were determined. RESULTS: Father-daughter and mother-daughter Spearman rank correlations coefficients in total cholesterol and LDL-C levels showed values ranging from 0.34 to 0.42 (p < 0.01). Correlation coefficients between both parents and between parents and sons were not significant. By stepwise multiple regression analysis it was found that parents' total cholesterol levels explained almost 30% of cholesterol variability in daughters and 10% in sons. This proportion was about 25% for LDL-C in daughters and was not significant in sons. Parent-children aggregation of HLD-C and triglycerides was weak. CONCLUSIONS: Parent-daughter aggregation of lipid and lipoprotein levels was stronger than parent-son, which has been evidenced mainly in total cholesterol and LDL-C. It has been found no evidence of relation between parents.     

Experience with special-type pacemaker leads (author's transl)

The dislodgement rate of endocardially placed pacemaker leads can be decreased by the use of special-type electrodes. Since 1963 a total of 2100 pacemaker implantations was performed. Since 1970 we have been using special-type electrodes in 15 to 20% of our patients each year. The complication rate of all pacemaker leads implanted in the period 1974 to 1978 was 7.6%, the rate of the special type electrodes alone came up to 15%. The lead IE--65--I had the greatest deal of this - 11 out of 43 leads had to be removed. 152 electrodes type IVE--85--armed with metal hooks - were implanted, 18 of which had to be revised and 17 of 117 rigid leads type IE--60--KS--10 revealed failure which made revision necessary. In contrast, 54 screw-in leads type 6957, Medtronik and AE--60--YR, Biotronik caused only one perforation - a lethal one. Primary experiences with a porous tip lead (CPII--4116) are good enough to recommend the use of this electrode as a lead of first choice. We saw 2 dislodgements in 50 implantations. Failure to sense or to pace were never seen (time of observation 2 to 18 months).     

Assessment of the subclavian vein in patients with transvenous pacemaker leads

Thrombosis of the subclavian vein can occur after the implantation of transvenous pacemaker electrodes. Although this is seldom followed by thromboembolic complications, it can cause problems when replacing the leads. To assess the impact of the pacemaker leads on the subclavian vein, a study using noninvasive duplex sonography was performed on 56 patients at an average of 41 months after the implantation. Forty-three percent of the patients were found to have a normal function of the subclavian vein, 46% developed pathological changes of the vessel wall, and 11% occluded. These changes rarely caused symptoms, and, therefore, had little clinical significance. Moreover, the occlusion rate was found independent of the patient's age, the patient's sex, the number of electrodes, the procedure of implantation, and even the time from implantation. As a result, the clinical diagnosis of occlusion is uncertain. Therefore, duplex sonography is recommended as an easy means of excluding a totally thrombosed subclavian vein prior to replacing pacemaker leads.     

Safety and effectiveness of placement of pacemaker and defibrillator leads in the axillary vein guided by contrast venography

OBJECTIVE: To identify subjects with univentricular idiopathic structural and/or functional myocardial disorders (as defined) and to describe the characteristic features. DESIGN: Over a period of 4 years, 1993-1996, all adult subjects were obtained consecutively from a centralised referral cardiological service. The subjects had to fulfil a set of formulated diagnostic criteria for each isolated type of univentricular disease-symptomatic or asymptomatic. The subjects were diagnosed on the basis of clinical features, supported by electrocardiographic, radiological and echocardiographic evidence of lone ventricular disease, with a further definition of abnormalities based on appropriately selected standard left and right heart assessments, inter alia: (i) cardiac catheterisation, including coronary arteriography and pulmonary angiography; (ii) radio-isotope studies-mibiscan; (iii) ventilation perfusion scan; and (iv) laboratory tests to identify likely cause(s) of diffuse myocardial damage as well as to recognise nonspecific effects of tissue damage and organ dysfunction. SETTING: A referral cardiological service of a tertiary academic hospital, which provides a consultative service for inpatients and ambulatory cases. All subjects were studied on admission to hospital. PARTICIPANTS: A set of criteria was formulated for each category of lone ventricular myopathy. A total of 30 patients were thus identified and included in the study-men and women ranging in age from 18 years to 84 years, with an average of 48 years. All were investigated after admission to hospital by means of a detailed set of investigations that rigorously excluded overt or occult causes of diffuse myocardial damage and any severe myocardial dysfunction secondary to haemodynamic conditions. Seven patients with significant coronary artery disease were excluded. Any subject with pulmonary or systemic hypertension was also excluded. MAIN OUTCOME MEASURES: Total number of patients, number of patients in each subgroup were analysed by age, sex, clinical features, and by special investigation. The mode of presentation and electrocardiographic features were analysed separately. RESULTS: Twenty-two left ventricular and 8 right ventricular cases of lone ventricular cardiomyopathy were diagnosed. All but 1 patient with right ventricular disease were symptomatic and 5 subjects with left ventricular myopathy were incidentally discovered. There were 17 men and 13 women in the series. Of the 8 patients with right ventricular disease, 6 were women, while of the 22 patients with left ventricular cardiomyopathy, 15 were men. CONCLUSION: The study supports the previously described existence of lone ventricular idiopathic cardiomyopathy. Further studies are, however, indicated in order to define its prevalence and nature more accurately, as well as to describe any relationship with univentricular cardiomyopathies, and define the characteristics of each category and the possible evolutionary patterns. Right ventricular cardiomyopathy is a new entity which may pose difficult diagnostic challenges, while left ventricular disease is generally accepted as a stage in the clinical spectrum of classic idiopathic dilated cardiomyopathy.     

针铁矿法喷淋除铁试验研究

巴彦淖尔紫金公司采用两段酸浸-黄钾铁矾法除铁工艺,一个锌系统每年浸出渣量为10万t/a,渣中含有大量的有价金属,其中铁30000t/a,锌4 000t/a,以及大量的铅和银金属,由于含硫较高,造成火法处理中尾气回收有很大的困难。通过研究发现,采用针铁矿法喷淋除铁后,大大降低了渣含硫,可以降低渣火法处理尾气回收的压力,同时由于不需要加入铵、钠等阳离子,也降低了生产成本。     

Surveillance of pacemaker patients by an automatic pacemaker function analyzer

This is a report of our experiences with the automatic contrast medium injector at selective coronary angiography during 836 examinations, and the quantitative evaluation of 193 single injections. Using average injection volumes per single injection of 5.0 ml for the left and 2.5 ml for the right coronary artery, a clear reduction of the quantity of contrast medium at constant definition can be registered. The variability in increase in the injection flow from 0 up to the peakflow appears to be important according to the anatomic and pathologic facts. Frequently a contrast medium reflux occurs out of the coronary ostium into the aorta. On the whole, automatic injection at selective coronary angiography is a reproducible and extensible method with few risks.     

玻璃包覆FeCoSiB微丝包覆层化学去除方法

以玻璃包覆FeCoSiB合金微丝为对象,研究了氢氟酸含量和反应温度对包覆层去除过程的影响,以及缓蚀剂对Fe-CoSiB芯丝的保护效果.结果表明:在反应温度为25℃的条件下,当所采用的HF质量分数从10%增加到40%时,玻璃包覆层去除速度从0.005μm·s^-1提高至0.076μm·s^-1;在HF质量分数为40%的条件下,当反应温度从10℃升高到45℃时,玻璃包覆层去除速度从0.033μm·s^-1提高到0.234μm·s^-1;反应温度为20~25℃时,用质量分数40%的氢氟酸溶液去除厚度范围为7.5~9.0μm高硼硅玻璃包覆层的最佳时间为150s;硫氰酸钠及硫氰酸钠+乌洛托品作为缓蚀剂均可显著抑制氢氟酸溶液对芯丝的腐蚀,硫氰酸钠+乌洛托品还可有效减少金属吸氢,有利于防止芯丝力学性能的劣化.

     

Effectiveness of caries removal by the partial tunnel preparation method

The tunnel preparation method is designed to remove approximal caries through a channel from the occlusal surface while preserving the marginal ridge. This method entails reduced access to the caries lesion and thereby uncertainty as to the complete removal of caries. The purpose of the present investigation was to study the effectiveness of caries removal in 60 extracted premolars and molars by the partial tunnel preparation method. The glass polyalkenoat (ionomer) filling and the distance to the pulp were also examined. Examination of the sectioned teeth showed residual caries in the axial wall of two teeth and in dentin close to the enamel lesion in 10 teeth. Very few porosities were found within the glass polyalkenoat material and at the interface between the filling and the cavity walls.     

基于游长标记的花纹板表面水痕去除方法

花纹板是众多钢材产品中的一种,由于其复杂的表面特性,导致现有的带钢表面质量在线检测系统无法布置。尝试通过对花纹板中一种最常见的伪缺陷——表面水痕,进行分析研究,给出一种在包含有纹理背景的情况下的缺陷检出方法,为在花纹板上布置带钢表面质量在线检测系统提供有效支撑。通过对图像像素灰度特性、梯度特性以及相互之间关联度特征进行分析,给出一种基于游长编码思想的花纹板表面水痕标记算法,通过该算法的应用,能够准确高效地定位图像上的水痕,为将水痕伪缺陷排除出花纹板缺陷提供技术保障。     

Pacemaker syndrome without a pacemaker

Circulatory consequences of cardiac arrhythmias are not always evident. Proper interpretation of the clinical symptoms in certain cases requires assessment of the patients' other hemodynamic characteristics. The authors present the case of a patient with left ventricular hypertrophy, who developed severe circulatory failure at the time of artrioventricular dyssynchrony in association with junctional rhythm. Analogy between the circulatory consequences of the junctional rhythm and ventricular pacing was documented by hemodynamic measurements. The patient was subsequently treated by implanting an atrioventricular pacemaker.     

Inhibition of a ventricular synchronous pacemaker

Noncompetitive ventricular synchronous pacemakers (VVT) have been available since 1965. Most presently available and earlier models have a single, fixed pulse-to-pulse interval divided into a total refractory period of 350 to 400 msec., followed by a sensitive period. During the refractory period the pacemaker will not respond to QSR complexes or electrical signals, but a pacer stimulus will be produced during the sensitive period. The generator cannot be inhibited under any circumstances. The Cordis Omni-Sctocor has a refractory period and two sensitive periods, during one of which the generator is inhibited. Unlike other ventricular synchronous pacers, the Omni-Ectocor is capable of inhibition by single or multiple ventricular or other signals, of slowing or increase of the stimulus formation rate which depends on the timing of the premature ventricular contractions, and of inhibition by a run of ventricular tachycardia or by electromagnetic interference. The rate of interference producing these effects is a function of the automatic rate to which the generator is programmed. All of these factors must be considered for proper interpretation of the ECG.     

Unusual dislocation of a pacemaker electrode

On the basis of an observation is reported on an uncommon dislocation of a separated pacemaker probe into the inside of the heart with a winding-up in the right ventricle. A massive thrombosis with embolus in the lungs developed by a parietal thrombosis in the region of the pacemaker cable. Diagnosing and secondary complications were described and therapeutic and prophylactic measures discussed. Such a complication of the pacemaker therapy must be absolutely excluded in spite of the increasing number of secondary surgical interventions in pacemaker patients.     

Percutaneous removal of a fractured and extruded telectronics accufix atrial retention wire: new approach preserving pacing function

We describe a two-generation family with combined clinical features of myoclonic epilepsy, progressive external ophthalmoplegia (PEO), proximal myopathy, pigmentary retinopathy, progressive deafness, basal ganglia calcification, and ragged-red fibers in a muscle biopsy specimen. One family member died unexpectedly at age 22 years. The molecular tests revealed an A-to-G transition at nucleotide position 3243 of the mitochondrial tRNA(Leu(UUR)) gene. No one in this family had stroke-like episodes. Although the propositus (a 28-year-old woman) had a significant number of white hairs, the percentage of mutant mtDNA in white-hair roots was not different from that in the colored-hair roots. Our findings suggest that the 3243 mutation can be associated with mixed clinical features of myoclonic epilepsy with ragged-red fibers (MERRF) and PEO and that a preferential increase in the levels of the mutant mtDNA is not related to graying of hair, and hence to the hypothesized production of premature aging of cells.     

Image of pseudocapture caused by micro-dislodgment of the electrode in a VDD pacemaker

The new AV sequential pacemakers have improved the suitability for the election of the best pacing mode for each patient. The complexity of the systems may mask some dysfunctions. In the presented case, a failure to capture due to micro-dislodgment, may have been missed in a simple pacemaker control, because of the combination of several factors: the presence of normal AV conduction at that moment, the concordance between the pacemaker stimulus and the conducted QRS complex and the similar morphology of the conducted and paced QRS complex.     

Mn-Ce-Nb-Ox/P84 catalytic filters prepared by a novel method for simultaneous removal of particulates and NO

The Mn-Ce-Nb-O_x/P84 catalytic filter for removal of particulates and NO simultaneous was prepared by a novel method(foam coating method). The process parameters including the concentrations of PTFE emulsion, particle size of catalyst and calcination temperature for preparation of catalytic filters were analyzed. In addition, the physical properties and performance for removal of NO(NH_3-SCR) and particulates of Mn-Ce-Nb-O_x/P84 catalytic filter prepared under the optimized parameters, were also systematic studied. Results show that the process parameters had significant influences on stability and performance of catalytic filter, The Mn-Ce-Nb-O_x/P84 catalytic filter prepared by foam coating method under the optimized parameters, has satisfactory physical properties and catalytic performance for removal of NO and particulates at 140-220 ℃. The NO removal efficiency of catalytic filter can reach95.3% at 200 ℃ as the catalyst loading amount is 450 g/m~2, Moreover,the dust removal efficiency of MnGe-Nb-O_x/P84 catalytic filter reaches as high as 99.98%, and the PM2.5 removal efficiency also reaches99.98%. The anti-sulfur performance of Mn-Ce-Nb-O_x catalytic filter is also attractive, after injecting150 ppm SO_2, the NO removal efficiency still retains up to 85%. It is indicated that the foam coating method can not only make a bond of high strength between catalyst and filter, but also make the catalytic filter possessing an excellent and stable performance for removal of NO and particulates.