AV间期对双腔起搏器植入患者LVEF、NT-proBNP的影响

目的探讨双腔起搏器植入患者不同AV间期起搏时左室射血分数(LVEF)、N-末端脑钠肽前体(NT-proBNP)的变化规律。方法选择植入双腔起搏器并患Ⅲ度房室传导阻滞的患者30例,设置11个AV间期(150ms、170ms、190ms……350ms),记录不同AV间期下的LVEF,找出最佳AV间期。分为研究组(AV间期调为最佳AV间期)15例,对照组(AV间期为出厂默认AV间期)15例,于术前、术后3个月分别记录LVEF、NT-proBNP。结果 AV间期自150ms开始增至210ms~230ms时,LVEF随AV间期的延长而增大,在AV间期210ms~230ms时达到最大,达峰值后又逐渐下降,LVEF在AV间期210 ms及230 ms时较AV间期210ms~230ms时降低(P0.05);研究组与对照组术前LVEF、NT-proBNP比较差异无统计学意义(P0.05),术后3个月,研究组LVEF较对照组显著升高,而NT-proBNP显著降低,差异有统计学意义(P0.05)。结论双腔起搏器不同AV间期可影响LVEF;将AV间期调至最佳AV间期有利于心功能和血流动力学的改善。     

双腔起搏器不同房室延迟对左心房功能的影响

目的：探讨双腔起搏器不同房室延迟（AVD）起搏时对左心房功能的影响。方法：选择植入双腔起搏器的40例患者,分为舒张功能正常组（20例）和舒张功能不全组（20例）。应用实时三平面应变率成像分别测算两组患者在不同AVD时左心房心肌在收缩期、舒张早期和舒张晚期平均峰值应变率（SRs、SRe和SRa）。结果：在舒张功能正常组,不同AVD起搏对左心房功能的影响不显著（P〉0．05）。在舒张功能不全组：①AVD自80ms开始增至250ms时,SRa随AVD的延长相应增大,在AVD为200ms时达到最大,达峰值后又逐渐下降,AVD为150ms、200ms时SRa和LAEF较AVD为80ms、100ms、250ms时明显升高[SRa：（-2．87±0．50）S-1、（-3．14±0．44）S-1,比（-2．35±0．53）S-1、（-2．55±0．52）S、（-2．55±0．49）S-1,LAEF：（46．00±3．67）％、（51．22±3．33）％比（37．99±3．56）％、（39．64±3．08）％、（43．78±3．83）％,P〈0．05];②当AVD为80ms、250ms时,SRs增大,SRe减小;AVD为200ms时SRs明显低于AVD为80ms时[（3．02±0．56）S。比（3．27±0．62）S-1,P〈0．05]。结论：不同房室延迟对舒张功能正常患者左心房功能的影响不明显,但对于单纯舒张功能不全的患者,适当延长房室延迟更有利于左心房的功能,改善血流动力学。     

双腔起搏器自动房室间期搜索功能的临床随访观察

目的 观察双腔起搏器自动房室间期搜索功能(AV Search)减少心室起搏的有效性及对血流动力学和快速房性心律失常的影响.方法 对两种DDD/R起搏器97例(有AV Search功能47例,无AV Search功能50例)患者术后半年内随访观察.结果 有AV Search功能组术后1、3、6个月右心室起搏百分比明显小于无AV Search功能组[(19.2±5.6)%vs(80.4±10.2)%,(17.8±6.6)%vs(75.3±9.5)%,(17.4±7.3)%VS[76.2±8.6]%,P<0.05].有AV Search功能组心脏指数、每搏量、左心室舒张末内径、左心房内径及患者心功能分级均无明显改善(P>0.05);而左心窒射血分数则高于无AV Search功能组(P<0.05).高频心房事件也显著减少((31±9)vs(49±11),P<0.05].结论 有AV Search功能DDD/R双腔起搏器在减少非必须的心室起搏,改善血流动力学,减少高频心房事件方面优于与无AV Search功能DDD/R起搏器.     

不同房室间期对双腔起搏左室收缩功能的影响

为探讨双腔起搏不同房室间期对左室收缩功能的影响及最佳房室间期 ,选择 18例置入DDD起搏器的病窦综合征患者 ,在DOO起搏方式下随机将房室 (AV)间期程控为 10 0 ,130 ,15 0 ,170 ,2 0 0ms,在超声心动图下观察左室收缩功能指标 ,每次测量间隔 5min以上。结果 :AV间期为 15 0ms时左室收缩功能最好 ,与AV间期为 10 0ms时相比 ,左室收缩功能明显改善。以心输出量 (CO)为标准 ,18例中有 9例AV间期在 15 0ms时CO最佳 ,5例在 2 0 0ms时CO最佳 ,3例在 170ms时CO最佳 ,1例在 130ms时CO最佳 ;以CO为标准 ,DOO起搏方式最佳AV间期为 16 6±2 4ms。结论 :双腔起搏的AV间期对左室收缩功能有重要的影响 ,以CO为标准 ,个体化地选择双腔起搏的最佳AV间期对改善患者的心脏功能有重要的意义。     

体表心电图在双腔起搏器房室传导间期最佳化中的价值

目的:探讨置入了双腔起搏器的患者,在随访时,根据体表心电图P波宽度调节房室传导间期(AV间期)对血流动力学的影响。方法:因高度或Ⅲ度房室传导阻滞而安装美墩力SD303双腔起搏器的患者31例。测量患者体表心电图自身P波宽度,和(或)心房起搏脉冲至起搏的P波末端的宽度,在此测量值上加100ms,分别设定双腔起搏器的感知AV间期和起搏AV间期。使用多普勒超声仪,分别在出厂常规设置的AV间期和根据体表心电图优化的AV间期设定值,进行超声检查。结果:经体表心电图调整AV间期后的左室每搏量、左室舒张末期容量和左室射血分数、左室充盈时间、二尖瓣血流速度时间积分,均高于常规出厂设置的AV间期,前三者差异显著(P<0.05)。结论:根据体表心电图中P波宽度的变化来调节AV间期,不但能获得良好的血流动力学效果,且由于其简单易行,而具有广泛的临床实用价值。     

应用超声心动图对双腔起搏器起搏房室间期的优化

目的 应用超声心动图技术观察双腔起搏器不同起搏房室间期(pacing atrioventricular delay,PAVD)起搏对即时左心收缩及舒张功能的影响.方法 40例三度房室阻滞行永久双腔起搏器植入的患者,采用彩色多普勒超声对PAVD进行优化,以超声心动图左心室最大心排出量(CO)为最佳PAVD,比较不同PAVD下左心室收缩及舒张功能.结果 不同PAVD产生不同左心室CO,最佳PAVD平均为(155.7±20.4)ms,其中70%患者PAVD为150 ms及175 ms;当最佳PAVD时舒张功能指标Tei指数,二尖瓣环室间隔速度(E'),二尖瓣血流频谱E峰/二尖瓣瓣环室间隔速度(E/E')等指标均处于最佳水平.结论 调整DDD起搏器PAVD不但能够改善左心室收缩功能,也可对舒张功能产生良性影响,植入DDD起搏器患者应加强随访,调整优化PAVD使起搏器发挥最佳效应.     

不同房室间期对右室起搏比例影响的研究

目的：研究不同AV间期对右室起搏比例的影响,并探讨如何进一步进行AV间期的优化。方法：2012年9月至2015年12月,入选在我院接受圣犹达双腔起搏器植入患者,根据病因,分为“病窦综合征（SSS）”及“房室传导阻滞(AVB)”组。所有患者为DDD起搏模式,植入时默认AV间期PV/AV：150/170ms（5286型）及150/200ms（5816、5826型）;植入两个月后,AV间期设为PV/AV：325/350ms;植入4个月后,打开自动自主传导搜索功能（5286型）及VIPTM功能（5816、5826型）,PV/AV按照5286型起搏器固定参数设置,即每间隔5分钟搜索3个心动周期,并设置搜索时间120ms。每次随访时记录心室起搏比例,以秩和检验比较不同设置对起搏比例的影响。结果： SSS组入选38例,AVB组入选41例。SSS组一例患者因持续性心房颤动终止研究。两组患者中,默认设置、最长AV间期设置及自主传导搜索设置时起搏比例中位数分别为：37% 、3%、5%（SSS组）,83%、50%、54%（AVB组）三种设置间差异存在显著性（P<0.05）,从数值上看,SSS组差异更显著。结论：可以通过延长AV间期减少右室起搏,但对起搏器治疗患者,首先推荐个体化设置。     

双腔起搏房室间期自动搜索功能对心室起搏及心功能的影响

选择30例接受具有自动AV间期搜索功能(auto AV search)的双腔DDD(R)起搏器治疗的病窦综合征患者。AV search打开时心室起搏(VP)比例,血浆脑钠肽(BNP)水平,左室Tei指数均较关闭时降低(P均<0.01),且血浆BNP水平、左室Tei指数与VP比例均存在较好的相关性(P均<0.05)。结论:双腔起搏器的auto AVsearch功能可有效减少非必须的右室起搏,促进自身心室激动,改善患者血流动力学效应。     

双腔起搏器治疗扩张型心肌病(并充血性心力衰竭)的A-V间期与血流动力学改变的关系

目的探讨不同A-V间期时双腔起搏治疗扩张型心肌病对心脏血流动力学的影响,寻找设置最佳A-V间期的方法。方法选择3例扩张型心肌病并充血性心力衰竭置入双腔起搏器的患者,于术后6个月时设置不同的A-V间期,在超声心动图下记录舒张期二尖瓣反流情况、心脏收缩、舒张功能指标。用Swan-Ganz导管测量相关血流动力学参数。结果3例扩张型心肌病并充血性心力衰竭置入双腔起搏器患者在A-V间期为100~120ms时射血分数(EF)、心排血量(CO)达到最大,心脏收缩、舒张功能指标,相关血流动力学参数得到明显改善。结论100~120ms的生理性起搏可改善扩张型心肌病并充血性心力衰竭患者血流动力学状况。     

心脏起搏器自动化功能对老年患者心功能的影响

目的观察具有自动AV间期搜索和起搏模式策略自动化功能的双腔心脏起搏器对老年患者减少心室起搏的有效性。方法选择置入DDD/R型双腔心脏起搏器的老年病态窦房结综合征(SSS)患者123例,分为实验组66例,平均年龄(76.5±6.8)岁,置入具备自动AV间期搜索和模式策略功能的美敦力公司Adapta系列起搏器;对照组57例,平均年龄(73.1±7.4)岁,置入不具备上述2种功能的美敦力公司Sigma AED、MED系列起搏器。术后1年内随访,观察心功能(NYHA)、程控获取右心室起搏(VP)百分比、心脏彩色超声心动科进行左心房内径(LAD)、左心室舒张末内径(LVEDD)的测量,计算LVEF,抽血检测N末端前体钠尿肽(NT-proBNP)水平,并进行对比。结果与对照组比较,实验组术后1年VP百分比降低[(39.7±35.2)%vs(91.7±2.6)%,P=0.02],LVEDD、LAD、LVEF均明显改善,差异有统计学意义[(51.5±3.9)mmvs(53.9±3.6)mm,(38.2±2.6)mmvs(42.0±4.5)mm,(54.8±7.7)%vs(50.1±12.3)%,P<0.05,P<0.01),实验组术后1年NT-proBNP水平较对照组明显降低[(180.2±19.4)ng/Lvs(269.2±23.6)ng/L,P<0.01]。结论具有起搏自动AV间期搜索和模式策略自动化功能的双腔起搏器可减少老年SSS患者VP百分比,改善心功能。     

Three layer functional model and energy exchange concept of aging process

Relying on a certain degree of abstraction, we can propose that no particular distinction exists between animate or living matter and inanimate matter. While focusing attention on some specifics, the dividing line between the two can be drawn. The most apparent distinction is in the level of structural and functional organization with the dissimilar streams of ‘energy flow’ between the observed entity and the surrounding environment. In essence, living matter is created from inanimate matter which is organized to contain internal intense energy processes and maintain lower intensity energy exchange processes with the environment. Taking internal and external energy processes into account, we contend in this paper that living matter can be referred to as matter of dissipative structure, with this structure assumed to be a common quality of all living creatures and living matter in general. Interruption of internal energy conversion processes and terminating the controlled energy exchange with the environment leads to degeneration of dissipative structure and reduction of the same to inanimate matter, (gas, liquid and/or solid inanimate substances), and ultimately what can be called ‘death.’ This concept of what we call dissipative nature can be extended from living organisms to social groups of animals, to mankind. An analogy based on the organization of matter provides a basis for a functional model of living entities. The models relies on the parallels among the three central structures of any cell (nucleus, cytoplasm and outer membrane) and the human body (central organs, body fluids along with the connective tissues, and external skin integument). This three-part structural organization may be observed almost universally in nature. It can be observed from the atomic structure to the planetary and intergalactic organizations. This similarity is corroborated by the membrane theory applied to living organisms. According to the energy nature of living matter and the proposed functional model, the decreased integrity of a human body's external envelope membrane is a first cause of the structural degradation and aging of the entire organism. The aging process than progresses externally to internally, as in single cell organisms, suggesting that much of the efforts towards the restoration and maintenance of the mechanisms responsible for structural development should be focused accordingly, on the membrane, i.e., the skin. Numerous reports indicate that all parts of the human body, like: bones, blood with blood vessels, muscles, skin, and so on, have some ability for restoration. Therefore, actual revival of not only aging tissue of the human body's membrane, but the entire human body enclosed within, with all internal organs, might be expected. We assess several aging theories within the context of our model and provide suggestions on how to activate the body's own anti-aging mechanisms and increase longevity. This paper presents some analogies and some distinctions that exist between the living dissipative structure matter and inanimate matter, discusses the aging process and proposes certain aging reversal solutions.     

Unusual responses of nocturnal pineal melatonin synthesis and secretion to swimming: Attempts to define mechanisms

Abstract: The effect of swimming at night on rat pineal melatonin synthesis was compared with that of light exposure at night. Rats were forced to swim at 0030 hr (lights out at 2000 hr) and sacrificed by decapitation 15 and 30 min later, immediately after swimming. Other groups of animals were exposed to white light (650μW/cm²) for 15 and 30 min at same time. Swimming caused a rapid and highly significant drop in the melatonin content in the pineal gland; however, the activity of N-acetyltransferase (NAT), the supposed rate limiting enzyme in the melatonin production, was not changed. Despite the drop in pineal melatonin levels, serum concentrations of the indole remained elevated in the rats that swam. In contrast, melatonin levels in the pineal and serum of light exposed rats fell precipitously, accompanied by a significant suppression of NAT activity. Since we anticipated that the strenuous exercise associated with swimming may induce release of artrial natriuretic peptide (ANP) from the heart, which in turn could cause the release of pineal melatonin, in a second study we injected physiological saline intravenously to stretch the cardiac muscle and release ANP. Three milliliters of normal saline was injected during the day into the jugular vein of anesthetized rats that were pretreated with isoproterenol to stimulate pineal melatonin production. Animals were killed 15 min after the saline injection, and pineal NAT activity and pineal melatonin levels were measured. The saline injections caused no alteration in the elevated levels of either NAT or melatonin. These data suggest that the disparity in pineal NAT activity (which was high) and pineal melatonin (which was low), in animals swum at night, may not be caused by ANP which is released during strenuous exercise such as swimming.     

Melatonin and photoperiodic time measurement: Seasonal breeding in the sheep

Abstract: Well-established circadian physiology supports the view that photoperiodic time measurement utilizes the coincidence between the presence of light and a photosensitive phase of a 'biological clock' to alter reproductive status—the so-called external coincidence model of seasonal breeding. In this review, we examine the mechanism whereby photoperiod interacts with presumed suprachiasmatic nuclei activity to allow endogenous melatonin to normally synchronize reproductive activity to the optimal time of year. The Romney Marsh sheep is particularly explored as an experimental model. It is suggested that the on/off activity of seasonal reproduction may be a robust mechanism able to be predictably manipulated by the judicious use of the light/dark cycle and exogenous melatonin, but firmly based on circadian principles.     

The immunoneuroendocrine role of melatonin

Abstract: A tight, physiological link between the pineal gland and the immune system is emerging from a series of experimental studies. This link might reflect the evolutionary connection between self-recognition and reproduction. Pinealectomy or other experimental methods which inhibit melatonin synthesis and secretion induce a state of immunodepression which is counteracted by melatonin. In general, melatonin seems to have an immunoenhancing effect that is particularly apparent in immunodepressive states. The negative effect of acute stress or immunosuppressive pharmacological treatments on various immune parameters are counteracted by melatonin. It seems important to note that one of the main targets of melatonin is the thymus, i.e., the central organ of the immune system. The clinical use of melatonin as an immunotherapeutic agent seems promising in primary and secondary immunodeficiencies as well as in cancer immunotherapy. The immunoenhancing action of melatonin seems to be mediated by T-helper cell-derived opioid peptides as well as by lymphokines and, perhaps, by pituitary hormones. Melatonin-induced-immuno-opioids (MHO) and lymphokines imply the presence of specific binding sites or melatonin receptors on cells of the immune system. On the other hand, lymphokines such as -γ-interferon and interleukin-2 as well as thymic hormones can modulate the synthesis of melatonin in the pineal gland. The pineal gland might thus be viewed as the crux of a sophisticated immunoneuroendocrine network which functions as an unconscious, diffuse sensory organ.     

Response of rat pineal melatonin to calcium, magnesium, and lithium is circadian stage dependent

Abstract: Herein we documented the response of pineal melatonin production to electrolytes known to be effective on pineal function in view of a possible circadian stage dependence. We studied the release of melatonin by perifused rat pineal glands at 2 different circadian stages corresponding to the middle of the light and dark periods, i.e., respectively, 7 and 19 HALO (Hours After Light Onset, L:D = 12:12). The initial efflux rates were, as expected, much higher in the perifusates of glands removed from rats sacrificed during the dark phase than of those removed during the light phase. After 3 hr of perifusion, melatonin release reached similar levels which were found constant up to the 8th hr of perifusion, whatever the circadian stage. Perifusion of the glands with physiological concentrations for the rat of calcium (5.2 mmol/1) and magnesium (1.34 mmol/1) resulted in a stimulatory effect on the pineal glands removed from rats sacrificed in the middle of the dark period (19 HALO), whereas no effects were observed on the pineal glands removed from rats sacrificed during the light (7 HALO). Lithium (0.28 and 0.55 mmol/1) was ineffective on melatonin release in pineal glands removed 7 and 19 HALO. Our results show differences in the initial efflux rates of melatonin and in the response of perifused pineal glands to calcium and magnesium according to the circadian stage.     

Serological survey of HIV and syphilis in pregnant women in Madagascar

Objectives Peripartal transmission of human immunodeficiency virus (HIV) and Treponema pallidum, the causative agent of syphilis, leads to severe consequences for newborns. Preventive measures require awareness of the maternal infection. Although HIV and syphilis testing in Madagascar could be theoretically carried out within the framework of the national pregnancy follow‐up scheme, the required test kits are rarely available at peripheral health centres. In this study, we screened blood samples of pregnant Madagascan women for HIV and syphilis seroprevalence to estimate the demand for systemic screening in pregnancy. Methods Retrospective anonymous serological analysis for HIV and syphilis was performed in plasma samples from 1232 pregnant women that were taken between May and July 2010 in Ambositra, Ifanadiana, Manakara, Mananjary, Moramanga and Tsiroanomandidy (Madagascar) during pregnancy follow‐up. Screening was based on Treponema pallidum haemagglutination tests for syphilis and rapid tests for HIV, with confirmation of positive screening results on line assays. Results Out of 1232 pregnant women, none were seropositive for HIV and 37 (3%) were seropositive for Treponema pallidum. Conclusions Our findings are in line with previous studies that describe considerable syphilis prevalence in the rural Madagascan population. The results suggest a need for screening to prevent peripartal Treponema pallidum transmission, while HIV is still rare. If they are known, Treponema pallidum infections can be easily, safely and inexpensively treated even in pregnancy to reduce the risk of transmission.