双腔起搏不同房室延迟对左室舒张功能的影响

目的探讨植入双腔起搏器（DDD）术后患者不同房室延迟（AVD）、不同起搏状态对左室舒张功能的影响。方法选择30例接受DDD心脏起搏器治疗的病窦综合征患者，术后随访时，通过程控调节患者的AVD，采用彩色多普勒超声心动图测量不同起搏状态下患者的Tei指数、早期二尖瓣减速时间（DT）与舒张早期运动速度，舒张晚期运动速度（Em／Am）等左室舒张功能指标，用免疫荧光法测定血浆B型利钠肽（BNP），并比较不同起搏状态下以上各指标的差异。结果部分起搏与全部起搏状态下的心脏彩超舒张功能指标及BNP比较差异有显著性（P〈0．01），全部下传与部分起搏状态下的心脏彩超舒张功能指标及BNP比较差异有显著性（P〈0．01）。结论全部下传状态下患者的左室舒张功能最佳，提示AVD的选择对植入DDD的病窦综合症病人有重要意义。     

Tissue Doppler imaging study of right ventricular myocardial systolic activation in subjects with pulmonary arterial hypertension

Background Tissue Doppler imaging （TDI） has provided an objective means to quantify global and regional left ventricular （LV） and right ventricular （RV） function with improved accuracy and greater reproducibility than conventional echocardiography. This study was conducted to assess RV myocardial systolic activation by TDI in subjects with pulmonary arterial hypertension （PAH）. Methods A total of 30 patients with PAH and 30 healthy volunteers, all comparable in age and sex, underwent standard Doppler echo and TDI. Using pulsed Doppler echocardiography combined with TDI, the following regional parameters were evaluated in three different myocardial segments （RV basal lateral wall, basal septal, and LV basal lateral） on apical 4-chamber view： systolic （Sm）, early- and late-diastolic （Em and Am） peak velocities. RV myocardial systolic activation delay was defined as the difference in time to peak TDI systolic velocities between the RV basal lateral wall and basal septal. In addition, RV end-diastolic and end-systolic areas were measured to calculate RV fractional area change from the same apical 4-chamber view. Results Compared with the control group, patients with PAH showed increased RA and RV end-diastolic diameter （RA： （4.5±1.2）cm vs （3.0±0.8）cm, P〈0.05 and RV： （4.8±1.9）cm vs （3.4±0.5）cm, P〈0.05） and reduced RV fractional area change; （35±14）% vs （56±9）%, P〈0.05. These PAH patients showed lower myocardial peak velocities and a significant activation delay compared with controls （P〈0.05）. Moreover, a strong correlation between RV myocardial systolic activation delay and RV fractional area change was shown in patients with pulmonary arterial hypertension （r = -0.82）. Conclusions In PAH, RV myocardial systolic activation was markedly delayed, which was directly related to the RV fractional area change. RV myocardial systolic activation delay assessed by TDI could offer a unique approach to predict RV dysfunction.     

双腔心脏起搏时房室延迟对左室充盈动力学的影响

①目的　探讨双腔心脏起搏时房室延迟对左室充盈动力学的影响。②方法　对 19例患有完全性房室传导阻滞并植入永久性双腔心脏起搏器的病人 (起搏频率为 70min-1,房室延迟分别程控在 70ms,15 0ms和2 30ms) ,应用脉冲多普勒记录不同房室延迟时的二尖瓣口和主动脉的血流频谱。测量左室舒张期充盈时间、舒张早期峰值充盈速度、舒张晚期峰值充盈速度、舒张早期和舒张晚期峰值充盈速度的比值、二尖瓣舒张期血流速度时间积分和主动脉收缩期血流速度时间积分。③结果　随着房室延迟的增加 ,左室舒张期充盈时间变短 (F =2 7.9,P <0 .0 0 0 1) ,舒张早期峰值充盈速度降低 (F =4 .8,P <0 .0 5 ) ,舒张晚期峰值充盈速度增加 (F =5 .0 ,P <0 .0 5 ) ,舒张早期和舒张晚期峰值充盈速度的比值减小 (F =11.1,P <0 .0 0 0 1)。舒张期二尖瓣口血流速度时间积分和收缩期左室流出道血流速度时间积分在房室延迟 15 0ms时最大 (F =8.0 ,5 .5 ,P <0 .0 1)。④结论　双腔心脏起搏时左室舒张期充盈模式随房室延迟的不同而变化 ,多普勒超声对左室充盈模式变化的评估有助于获取双腔心脏起搏的最佳的血流动力学效应。     

Atrial sensing and pacing with a single pass ventricular lead

The use of single lead for atrial synchronous ventricular (VDD) pacing in patients with high grade atrioventricular (AV) block and normal sinus node function is an acceptable alternative to dual chamber (DDD) pacing. Implantation and follow up procedures are simplified, and cost is usually reduced by more than the cost of an additional atrial lead. With the use of either diagonally arranged dipole or closely spaced ring electrodes, reliable atrial sensing can be achieved using differential atrial amplifier and high atrial sensitivity. Also oversensing is infrequently observed using provocation tests and dynamic recordings, clinical undersensing is unusual and minimized by programming to the highest atrial sensitivity. However, as atrial pacing is not possible, loss of AV synchrony and rate response may occur for unrecognized or progressive sinus node disease and lower rate limit. The development of single lead dual chamber pacing system may overcome this limitation. Recent studies have demonstrated that atrial pacing can be effective either with the use of a special pacing lead configuration or via floating atrial electrode with a novel stimulation method. Overlapping biphasic impulse (OLBI) can reduce atrial pacing threshold. Early clinical experience suggested that this new pacing method can provide effective and reliable atrial pacing with a relatively low incidence of diaphragmatic pacing. Thus the problem of atrial sensing is solved with a single pass lead but further long term evaluation is required to assess the efficacy and feasibility of new instrumentation for single lead dual chamber pacing.     

Decreased small arterial compliance with increased serum vascular endothelial growth factor-A and circulating endothelial progenitor cell in dilated cardiomyopathy

Background Evidence showed that both myocardium and blood vessels were damaged in dilated cardiomyopathy （DCM）. However, the changes in arterial compliance, serum cytokines and circulating endothelial progenitor cells （EPC）, and their correlations remain unknown.
Methods Sixty-five DCM patients and 49 healthy volunteers were studied. Both large artery compliance （C1） and small artery compliance （C2） were measured with the CVProfUor DO-2020. Quantitative enzyme-linked immunosorbent assays （ELISAs） were used to measure the levels of vascular endothelial growth factor-A （VEGF-A） and VEGF receptor 2 （VEGF-R2）. Circulating EPC was assessed by EPC colony-forming assays and flow cytometry （CD133^＋/CD34^＋cells）. Phagocytized Dil-acLDL and binded FITC-UEA-I were used to analyze endothelial lineage marker expression by immunofluorescence.
Results Although C2 was markedly lower in DCM patients than in control group （（3.8±1.8） ml/mmHg × 100 vs （5.0±2.2） ml/mmHg × 100, P〈0.0001）, there was no statistically significant difference in C1 between the two groups （P〉0.05）. Levels of VEGF-A, the numbers of colony-forming units （CFU） and the fractions of EPC were obviously higher in DCM patients than in control group （（127.6±139.5） pg/ml vs （58.8±42.9） pg/ml, P〈0.0001; （2.5±1.5）% vs （0.5±0.3）%, P〈0.05; 23.5±12.8 vs 10.8±7.4, P〈0.01, respectively） and however, there was no significant difference in VEGF-R2 between two groups （P〉0.05）. LgVEGF-A was positively correlated with the number of EPC-CFU （r=-0.435; P〈0.05） and inversely correlated with C2 （r=-0.543; P〈0.001） in DCM patients. Conclusions The reduction of C2, a sensitive marker reflecting endothelial dysfunction, was observed in DCM patients and closely related to the increase in serum VEGF-A.     

Impact of automatic threshold capture on pulse generator longevity

The AutoCapture (AC) system confirms the cardiac response to pacing stimuli and automatically adjusts output close to the pacing threshold, thus resulting in substantial battery savings and greater stimulation safety for patients.1-4 In 1995, St. Jude Medical successfully introduced the first AC system in the single chamber Microny Pacemaker. In 1999 the first, dual chamber, pacemaker system with the AC technology and low polarization, low threshold, bipolar lead was released, the Affinit…     

Changes of hypothalamus-pituitary hormones in patients after total removal of craniopharyngiomas

CraniopharyngiomaisabenigntumorwhichisoriginatedfromtheremnantsofthefetalRathkepouch Itiswellknownthatcraniopharyngiomausuallycausesendocrineabnormalitiesbecauseofthecloserelationshipbetweenitsoriginandthehypothalamus Althoughtherehasbeencontroversyaboutitsmanagement,neurosurgeonstendtoseektotalremovalofthetumorattheinitialtreatmentinrecentyears 1 ,2 　Howeverendocrinedeficitsaftertotalresectionofthetumorarecommon Thomsettetal3observedmoreendocrinedeficitsaftertotalremovalofcraniopharyngiomat…     

双源CT心电门控管电流调节模式扫描对左心室功能的评估

目的：与超声心动图（ECG）检查对照,评估双源CT（DSCT）心电门控管电流调节模式心脏扫描对冠心病患者左心室功能评估的准确性。方法50例冠心病患者进行心电门控管电流调节模式下DSCT检查及经胸二维ECG检查（双平面Simpson法）,将ECG对心功能参数的测量结果作为对照,评估DSCT测量值的准确性。结果 DSC T所获心脏舒张末期时相范围为90％-100％ R‐R间期,收缩末期时相范围为30％-40％R‐R间期。DSCT心内、外膜轮廓手动校正前左心室舒张末期容积（EDV ）、收缩末期容积（ESV ）、每搏输出量（SV）测量值均大于校正后（P＜0.001）,但校正前后左室射血分数（LVEF）测量值差异无统计学意义（P＞0.05）。DSCT与ECG对EDV、ESV、SV及LVEF的测量值差异均无统计学意义（P＞0.05）,且两种检查方法所得的各项测量值具有高度相关性（P＜0.001）,Bland‐Altman分析示两种检查方法的测量结果一致性较好。结论双源CT回顾性心电门控结合心电门控管电流调节技术能满足左心功能分析的需要,对左心室形态学参数及其功能的评估准确、可靠。     

清醒犬慢性充血性心力衰竭模型的血流动力学特征

目的:评价犬心肌梗死后快速起搏法建立的类似人类慢性充血性心力衰竭模型的血流动力学特征。方法：5只健康雄性比格犬在全身麻醉下接受开胸手术,安置测压、测距装置和心脏起搏导线后结扎冠状动脉左前降支,6周后以220～260次/min行右心室起搏诱导犬充血性心力衰竭。术前进行多普勒超声心动图检测,起搏前及起搏4周后分别观测和记录多普勒超声心动图和血流动力学数据。结果：手术前和起搏前LVEDD,LVEF和FS的变化均无统计学意义（P＞0.05）。与起搏前比较,起搏4周后LVEDD和LVEDP明显增高（P＜0.05）,起搏后和起搏前LVEDD分别为(44.71±3.35) mm和(38.01±1.54) mm,LVEDP分别为(25.63±1.86) mmHg和(10.58±1.23) mmHg（P＜0.05）,起搏后LVEF,FS,LV dp/dt max较起搏前显著降低（P＜0.01）。结论：比格犬心肌梗死后快速起搏制备的心力衰竭模型的左心室结构和血流动力学变化特点与人类心力衰竭相似。     

Effects of right atrial and ventricular DDD pacing on cardiac function and ventricular contraction synchrony

Background Right ventricular apical pacing has been reported to reduce cardiac performance. But there are few reports on the effects of dual chamber (DDD) pacing on cardiac function compared to sinus rhythm. In this study, we evaluated the effects of right atrial and ventricular DDD pacing on cardiac function and ventricular contraction synchrony using equilibrium radionuclide angiography. Methods Ten patients implanted with a right atrial and ventricular DDD pacemaker underwent equilibrium radionuclide angiography. The scintigraphic data were obtained during sinus rhythm and pacing rhythm. Cardiac function parameters were obtained semimanually. Phase analysis was used to study the ventricular activation sequence and ventricular synchrony. Results The left ventricular 1/3 ejection fraction decreased significantly during pacing compared with that during sinus rhythm［(23.4±6.1)% vs (27.7±4.5)%, P=0.01］. Regional ejection fraction also decreased during pacing, although the difference was not statistically significant. Phase analysis showed that the right ventricle was activated earlier than the left ventricle during pacing, and that the phase shift was significantly greater during pacing than that during sinus rhythm［64.13°±16.80° vs 52.88°±9.26°, P=0.007］. The activation of both ventricles occurred simultaneously during sinus rhythm, with the activation sequence from proximal septum or base of left ventricle to apex. The earliest activation during pacing occurred at the right ventricular apex, and subsequently spread to the base and left ventricle.Conclusion Right atrial and ventricular DDD pacing impairs left ventricular systolic function and ventricular synchrony.     

不同起搏方式对QT离散度的影响

目的　探讨起搏器植入患者起搏前后QT离散度 (QTd)的变化。方法　采用美国产十二导联心电图仪同步记录 ,计算分析两组不同起搏方式QTcd(其中VVI起搏组 30例 ,DDD起搏组 19例 )的QTd变化。结果　以DDD起搏方式明显优于VVI起搏方式 ,起搏后 2～ 3天 ,DDD起搏组的QTcd较VVI起搏组明显减少 (t =2 .14 ,P <0 .0 5 )。结论　DDD起搏方式保留良好的房室顺序起搏 ,起搏后血流动力学改善 ,心肌复极趋于一致性 ,心电活动稳定。     

Imbalance of endogenous homocysteine and hydrogen sulfide metabolic pathway in essential hypertensive children

Background  Hypertension is a common disease of the cardiovascular system. So far, the pathogenesis of primary hypertension remains unclear. The elaboration of its pathogenesis is an important topic in the field which calls for urgent resolution. The aim of this study was to probe into the metabolic imbalance of homocysteine (Hcy) and hydrogen sulfide (H₂S) in children with essential hypertension, and its significance in the pathogenesis of essential hypertension.
Methods  Twenty-five children with essential hypertension and 30 healthy children with normal blood pressure were enrolled in the study. The medical history was investigated and a physical examination was conducted on the subjects. Plasma Hcy content was examined by fluorescence polarization immunoassay (FPIA). The plasma H₂S level was detected by a modified method with a sulfide electrode. Data were presented as mean±standard deviation. The t test was applied to the mean values of both groups. Pearson linear correlation analysis was applied to the plasma Hcy and H₂S as well as to the systolic pressure against the plasma H₂S/Hcy ratio.
Results  Plasma Hcy, an intermittent metabolite of the endogenous methionine pathway, was markedly increased but plasma H₂S, a final product of this pathway was significantly decreased in hypertensive cases when compared with normal subjects ((Hcy: (12.68±9.69) µmol/L vs (6.62±4.79) µmol/L (t=2.996, P<0.01); H₂S: (51.93±6.01) µmol/L vs (65.70±5.50) µmol/L) (t=-8.670, P<0.01)). The ratio of plasma H₂S/Hcy in children with hypertension was 5.83±2.91, while that of the control group was 11.60±3.30, and the difference is significant with a t=-6.610 and P<0.01. A negative correlation existed between plasma Hcy and H₂S concentrations, r=-0.379, P<0.05. And a negative correlation was found between systolic blood pressure and the plasma H₂S/Hcy ratio, r=-0.687, P<0.05.
Conclusion  There was a metabolic imbalance of homocysteine and hydrogen sulfide in essential hypertensive children.

     

Inhibitory effect of tea polyphenols on renal cell apoptosis in rat test subjects suffering from cyclosporine-induced chronic nephrotoxicity

Objective To investigate the inhibitory effect of tea polyphenols on renal cell apoptosis in rat test subjects suffering from cyclosporine A (CsA)-induced chronic nephrotoxicity.Methods Four groups of rats with CsA-induced chronic nephrotoxicity were respectively treated with vehicle olive oil, tea polyphenols, CsA and tea polyphenols plus CsA. At the end of the 28th day of treatment, 24 hours urine and blood samples were obtained, and the animals were then sacrificed. The serum and urine samples were analysed for creatinine clearance, and kidney tissue was used for pathologic analysis of renal tubular injury and interstitial fibrosis. The TUNEL assay, apoptosis-related enzyme caspase-3 mRNA detected by RT-PCR, and its enzymatic activity were analysed for the possible detections of cell apoptosis.Results CsA-treated rats displayed increased apoptosis of the tubular and interstitial cells, in comparison with vehicle-treated controls (18. 3±4. 6 vs 4. 8±1.3 cells/mm2, P < 0. 05 ) . In comparision with a     

右室心尖部与右室流出道起搏近期效果比较

目的评价右心室流出道(RVOT)起搏和右心室心尖部(RVA)起搏对心脏同步性和心功能的影响。方法 41例病态窦房结综合征、高度及完全房室传导阻滞病人根据心室起搏电极植入部位的不同,分为RVOT起搏组(21例)和RVA起搏组(20例)。分别于术前和术后3、12个月通过超声心动图分别对病人左心室舒张末内径(LVEDD),左心室收缩末内径(LVESD)、左心室射血分数(LVEF)、室间隔和左心室后壁之间的运动延迟(SP-WMD)、心室间机械延迟时间(IVMD)等指标进行观察随访。结果术后3、12个月时,RVOT起搏组的LVEDD、LVESDI、VMD和SPWMD均明显小于RVA起搏组,LVEF均明显高于RVA起搏组(t=2.14~12.61,P<0.05)。结论 RVOT起搏较RVA起搏更有利于双心室电激动的同步性,且对心功能的不良影响较小。     

Anteroapical aneurysm plication improves mechanical intraventricular dyssynchrony in patients with anterior myocardial infarction

Background  Left ventricular (LV) dyssynchrony has been described to occur in patients with myocardial infarction. Dyssynchrony of left ventricular mechanical contraction produces adverse hemodynamic consequences. This study aimed to test the capacity of geometric rebuilding by aneurysm plication to restore a more synchronous contractile pattern after a mechanical, rather than electrical, intervention.

Methods  A total of sixty patients with anterior myocardial infarction, QRS duration <120 ms, electively undergoing operation between January 2008 and January 2010 were included for analysis. Real-time 3-dimensional echocardiography was performed to assess LV function, LV systolic and diastolic dyssynchrony by measuring ejection fraction (EF), peak ejection rate (PER), peak filling rate (PFR) and LV dyssynchrony. LV dyssynchrony was defined as the systolic dyssynchrony of the time to reach the minimum systolic volume for 16 LV segments, expressed in percent cardiac cycle, systolic dyssynchrony index (SDI). We compared changes of LV dyssynchrony at different interval times.

Results  LV contraction was significantly asynchronous because preoperative SDI was higher, EF, PER and PFR were lowered. Compared with function after operation, LV mechanical intraventricular resynchronization was improved with decreased SDI ((8.7±0.5) % vs. (14.3±1.6) %, P=0.01); LV function was improved with EF increasing ((43±9)% vs. (37±7)%, P=0.001), and LV systolic and diastolic dyssynchrony was improved with more rapid PFR (199.4±15.6 vs. 148.4±21.2, P=0.002) and PER (212.4±14.5 vs. 156.3±26.2, P=0.001).

Conclusions  Systolic and diastolic dyssynchrony was highly prevalent in patients with aneurysm, irrespective of QRS duration. Aneurysm plication produces a mechanical intraventricular resynchronization.

     

Effect of nifekalant on acute electrical remodelling in rapid atrial pacing canine model

Atpresent, treatment of atrial fibrillation (AF) with antiarrhythmic drugs is problematic, a better understanding of the mechanisms determining antiarrhythmic drug efficacy would help in improving therapy.1 Recent evidence indicates that disease or arrhythmic induced alterations in cardiac electrophysiology (electrical remodelling) are central in arrhythmic genesis, Aparticularly for AF, which alters cardiac electrophysiology to promote its own maintenance.2,3 Pharmacological therapy to prev…     

双腔起搏器最小化心室起搏功能中心室起搏管理与房室间期自动搜索功能的比较分析

目的:比较最小化心室起搏中心室起搏管理(MVP)与房室间期自动搜索[Search AV(+)]功能对右室起搏比例(VP％)及左室射血分数(LVEF)的影响.方法:50例症状性窦缓、病态窦房结综合征、间歇性房室传导阻滞的患者,均安装双腔起搏器,分为MVP组和Search AV(+)组,程控MVP组关闭Search AV(+)功能,开启MVP功能;Search AV(+)组开启Search AV(+)功能.于术后随访,比较其6个月的心房起搏、心室起搏比例、高频心房事件次数,及LVEF的值.结果:50例患者完成随访,MVP组比Search AV(+)组的心室起搏比例、高频心房事件次数都显著降低,分别为(11.4±8.3)％,(36.7±7.4)％和(32±10)次,(86±16)次;6个月的LVEF值较术前有显著差异,两组心房起搏比例、12个月的LVEF值差异无统计学意义.结论:MVP功能与SearchAV(+)功能相比可更加减少不必要的右心室起搏,减少高频心房事件.     

Assessment of cardiac function and synchronicity in subjects with isolated bundle branch block using Doppler imaging

Background Using tissue Doppler imaging and conventional echocardiographic technique, we examined the cardiac function and synchronicity in individuals with isolated right bundle branch block （RBBB） or left bundle branch block （LBBB） and assessed the relationship between QRS duration and synchronicity.     

Electrical remodeling of membrane ionic channels of hypertrophied ventricular myocytes from spontaneously hypertensive rats

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Opposite effects of WEB2086 on angiogenesis in atheromas and ischemic hindlimb of apoE gene deficient mice

Background  Our previous research has suggested that platelet activating factor receptor was related to atherosclerosis. The present study investigated the effect of a platelet activating factor receptor antagonist- WEB2086 on angiogenesis in aortal plaque and ischemic hindlimb of apolipoprotein E-deficient mice.
Methods  Eight-week-old apolipoprotein E-deficient mice were fed with a 0.15% cholesterol diet to develop advanced lesions. At age 32 weeks unilateral hindlimb ischemia was surgically induced and the mice were divided into two groups: with or without WEB2086 mixed with their drinking water (4.3 mg in 100 ml). At age 40 weeks blood was collected from the orbit for measurement of serum lipids and an enzyme linked immunosorbent assay was used to determine platelet activating factor and oxidized low density lipoprotein in the gastrocnemius and aorta. Whole-Mount CD31 stain and plaque-associated sprouting have been used to estimate angiogenesis in plaque from the aorta and laser Doppler perfusion imaging and immunohistochemical expression of von Willebrand factor have been used to estimate angiogenesis in ischemic hindlimb.
Results  The lipid composition of serum was not different between the groups. However, the amount of platelet activating factor and oxidized low density lipoprotein detected in the aorta was significantly higher than that in the gastrocnemius of ischemic hindlimb. The ratio of lesion to aorta levels was significantly reduced by administration of WEB2086, (31.52±6.18)% vs (55.58±8.34)%, P<0.01. The mean density of intimal capillaries in atherosclerotic plaque, (31.13±9.20)% vs (57.74±11.28)%, P<0.01, and the mean number of sprouts per aorta were significantly reduced, 183.92±34.17 vs 392.54±76.79, P<0.01, in the WEB2086 group. Blood flow (0.85±0.12 vs 0.45±0.06, P<0.01) and capillary density of ischemic hindlimb (1.18±0.17 vs 0.53±0.09, P<0.01) were markedly increased in apolipoprotein E-deficient mice treated with WEB2086 versus controls.
Conclusion  The study provides evidence that WEB2086 can inhibit angiogenesis in atherosclerotic plaque but promote it in ischemic hindlimb.