主动固定螺旋电极在右室流出道间隔部起搏中的应用体会

目的探索采用主动固定螺旋电极行右室间隔部起搏的临床可行性。方法随机选择54例需要安装双腔起搏器的患者行右室流出道间隔部起搏,将心室起搏螺旋电极先后定位于右室心尖部及右室流出道间隔部并测试起搏参数。结果右室流出道间隔部电极定位成功率为98.15%,该部位起搏参数满足起搏要求,同时起搏的QRS波时限较心尖部变窄(130.45±18.24msvs153.11±20.10ms,P<0.001)。结论采用主动固定螺旋电极行右室流出道间隔部起搏安全性高、可行性好。     

Lead I R‐wave amplitude to distinguish ventricular arrhythmias with lead V3 transition originating from the left versus right ventricular outflow tract

BackgroundThe electrophysiology algorithm for localizing left or right origins of outflow tract ventricular arrhythmias (OT‐VAs) with lead V₃ transition still needs further investigation in clinical practice.HypothesisLead I R‐wave amplitude is effective in distinguishing the left or right origin of OT‐VAs with lead V₃ transition.MethodsWe measured lead I R‐wave amplitude in 82 OT‐VA patients with lead V₃ transition and a positive complex in lead I who underwent successful catheter ablation from the right ventricular outflow tract (RVOT) and left ventricular outflow tract (LVOT). The optimal R‐wave threshold was identified, compared with the V₂S/V₃R index, transitional zone (TZ) index, and V₂ transition ratio, and validated in a prospective cohort study.ResultsLead I R‐wave amplitude for LVOT origins was significantly higher than that for RVOT origins (0.55 ± 0.13 vs. 0.32 ± 0.15 mV; p < .001). The area under the curve (AUC) for lead I R‐wave amplitude as assessed by receiver operating characteristic (ROC) analysis was 0.926, with a cutoff value of ≥0.45 predicting LVOT origin with 92.9% sensitivity and 88.2% specificity, superior to the V₂S/V₃R index, TZ index, and V₂ transition ratio. VAs in the LVOT group mainly originated from the right coronary cusp (RCC) and left and right coronary cusp junction (L‐RCC). In the prospective study, lead I R‐wave amplitude identified the LVOT origin with 92.3% accuracy.ConclusionLead I R‐wave amplitude provides a useful and simple criterion to identify RCC or L‐RCC origin in OT‐VAs with lead V₃ transition.     

Utility of risk scores to predict adverse events in cardiac lead extraction

Introduction: Increasing device implantations, patient comorbidities, and longer life expectancy contribute to an increased need for lead extraction. Even if transvenous lead extraction (TLE) is a highly successful procedure, some serious procedural complications are reported. In order to identify those patients who are at higher risk, risk stratification scores were proposed.

Areas covered: The major obstacles to lead extractions are represented by the body’s response to the foreign implanted material and by the following development of fibrotic reaction between the lead and the vascular system. Several clinical factors and device features are associated with major complications and worse outcomes. Although different multiparametric scores predicting the safety and the efficacy of TLE procedures were reported, none of these scores were prospective evaluated.

Expert commentary: A correct risk stratification is needed in order to refer complex patients to centers with proven experience and avoid futile procedures. Furthermore, the identification of high-risk patients allows to perform the extraction procedure in the operating room instead of electrophysiology lab. Albeit some risk scores able to predict adverse event in cardiac lead extraction were described, there are still several limitations to their use and reproducibility.     

Sources,symptoms and characteristics of childhood lead poisoning: experience from a lead specialty clinic in China

Objectives: This study explored the sources of lead exposure, identified patients’ geographic distribution and evaluated the symptoms of children with elevated blood lead levels (BLLs) referred to a pediatric lead specialty clinic in China.

Material and methods: Data were collected from 515 consecutive outpatients attending the Pediatric Lead Poisoning Clinic in Xinhua Hospital, Shanghai, China, between 2011 and 2016, referred for BLLs ≥5?μg/dL. Atomic absorption spectrometry was used to measure venous BLLs.

Results: The mean?±?standard deviation age of the patients was 4.1?±?3.2 years. Their BLLs ranged from 5 to 126?μg/dL. The geometric mean and median BLLs were 24 and 26?μg/dL, respectively. Two hundred and twenty-two children (43.1%) were exposed to industrial lead pollution—mainly from Zhejiang, Jiangsu, Hunan, Henan and Anhui provinces; whereas, 41.4% (213 cases) were induced by folk medicines used widely throughout China. Other nonindustrial sources of lead exposure included lead-containing tinfoil and tin pots. Household lead paint was a rare source. Most patients exhibited nonspecific symptoms, such as hyperactivity, attention difficulty, aggressiveness, constipation and anorexia.

Conclusions: Industrial pollution and folk medicines are important sources of lead exposure in China. Childhood lead poisoning may be difficult to diagnose clinically as symptoms are nonspecific. Thus, blood lead screening may be necessary to identify children at high risk of exposure. Education to raise the awareness of potential sources of exposure resulting in their elimination would be expected to decrease the incidence of children with elevated BLLs.     

The suitability of EBC-Pb as a new biomarker to assess occupational exposure to lead

Occupational exposure to lead (Pb) requires continuous surveillance to assure, as much as possible, safe and healthful working conditions. This study addresses the suitability of assessing Pb exposure in relevant workers using their exhaled breath condensate (EBC). This study enrolled workers of two different Pb processing industries characterized by moderate and high Pb exposure levels in the work environment, and a group of non-exposed individuals working in offices who served as baseline for Pb exposure. The EBC-Pb of workers reflected the Pb levels in the work environment of all three settings, although the relationship with B-Pb was not clear. The lack of correlation between EBC-Pb and B-Pb most probably indicates the time lag for Pb to enter in the two body pools. The EBC-Pb seems to reflect immediate exposure, providing a prompt signature of Pb in the environmental that may interact directly with the organ. By delivering short-term evaluation of exposure, EBC-Pb represents a clear advantage in biomonitoring and may become an interesting tool for estimating organ burden.     

Early chronic lead exposure reduces exploratory activity in young C57BL/6J mice

Research has suggested that chronic low‐level lead exposure diminishes neurocognitive function in children. Tests that are sensitive to behavioral effects at lowest levels of lead exposure are needed for the development of animal models. In this study we investigated the effects of chronic low‐level lead exposure on exploratory activity (unbaited nose poke task), exploratory ambulation (open field task) and motor coordination (Rotarod task) in pre‐adolescent mice. C57BL/6J pups were exposed to 0 ppm (controls), 30 ppm (low‐dose) or 230 ppm (high‐dose) lead acetate via dams’ drinking water administered from birth to postnatal day 28, to achieve a range of blood lead levels (BLLs) from not detectable to 14.84 µg dl^–1). At postnatal day 28, mice completed behavioral testing and were killed (n = 61). BLLs were determined by inductively coupled plasma mass spectrometry. The effects of lead exposure on behavior were tested using generalized linear mixed model analyses with BLL, sex and the interaction as fixed effects, and litter as the random effect. BLL predicted decreased exploratory activity and no threshold of effect was apparent. As BLL increased, nose pokes decreased. The C57BL/6J mouse is a useful model for examining effects of early chronic low‐level lead exposure on behavior. In the C57BL/6J mouse, the unbaited nose poke task is sensitive to the effects of early chronic low‐level lead exposure. This is the first animal study to show behavioral effects in pre‐adolescent lead‐exposed mice with BLL below 5 µg dl^–1. Copyright © 2014 John Wiley & Sons, Ltd.     

株洲市门诊儿童血铅水平及其影响因素的流行病学研究

目的了解株洲市门诊儿童血铅水平及其影响因素,为防治铅中毒提供针对性建议。方法对株洲地区儿科门诊的1 200例1月~14岁儿童进行问卷调查,并测定其静脉血铅水平和血清铁、钙、铜、镁、锌含量。结果 1)门诊儿童血铅水平平均为(96.1±64.4)μg/L,≥100.0μg/L者检出率达28.7%。2)逐步回归分析:血铅水平与全血铁、钙、铜含量呈负相关,而不认为血铅水平与全血镁、锌含量存在显著关系。3)Logistic回归分析:母亲年龄较大、常补充钙/铁/锌制剂、常食用乳类和乳制品、散居是儿童血铅含量≥100μg/L的保护因素。母亲文化程度低、父亲吸烟、男童、常在交通繁忙地带散步/玩耍、进食前几乎不洗手、常咬文具/玩具、常食爆米花、常吸吮手指/啃手指甲、常玩橡皮泥、常服中草药、经常饮用罐装饮料、住所距离主干道较近、居室有墙皮脱落、住所楼层较低、大年龄儿童是儿童血铅含量≥100μg/L的危险因素。结论株洲市门诊儿童血铅水平≥100.0μg/L检出率较高,当地政府和社会应以改善生态环境、加强营养干预、普及健康教育、落实行为指导为切入点,减轻儿童铅暴露及其危害。