Hemodynamics in Childhood Hypertension

Children with elevated systolic blood pressure have a wide range of cardiac output. We investigated the mechanisms regulating resting and exercise blood pressure in 264 children who were selected from the low, middle, and upper quintile of the distribution of blood pressure of an entire school population. We identified patterns of response to exercise that correlated both with resting cardiac output and resting blood pressure. During isometric exercise, systolic blood pressure adjusted for age and body size increased in all groups. The low group mean pressure remained significantly lower than the high group's pressures throughout the entire exercise period. Body size adjusted group systolic and diastolic blood pressure level differences existed during dynamic exercise. The product of the systolic blood pressure times the heart rate in the high blood pressure group was significantly higher throughout dynamic exercise than in the other two groups. Elevated resting resistance was correlated with elevated resistance during isometric exercise and elevated diastolic blood pressure during dynamic exercise. Cardiac index had a significant negative correlation to age (r=-0.58) at all levels of blood pressure. This observation, in children, lends some support to the concept of evolution from a hyperkinetic circulation in early childhood to a circulation with lower cardiac output and more elevated systemic vascular resistance at an older age.     

Time-dependent diagnostic performance of a rapid troponin T version 2 bedside test in patients with acute coronary syndromes

The present investigation confirmed a former report of a diurnal variation with an increased urinary excretion rate of total glycosaminoglycans in the daytime [4]. Fractionation showed that this increase was solely due to three electrophoretic fractions which resisted degradation with chondroitinase ABC. Fasting in the daytime had no influence on the increased excretion of one of these fractions, whereas it prevented the increased excretion of the other two (probably both heparan sulphates). The excretion rates of chondroitin 4/6 sulphate, dermatan sulphate and a fourth chondroitinase ABC resistant glycosaminoglycan (heparan sulphate) were uninfluenced by time of day and fasting. This was contrary to the excretion of hydroxyproline which decreased during the fasting period.     

Robotic stabilisation assisting cardiac surgery on beating hearts

Minimally invasive direct coronary artery bypass (MIDCAB) requires precise work on beating hearts and demands of surgeons' manual dexterity and mental concentration. We propose a surgical robot system that compensates for motions of organs during operations. The motion-cancelling robot system consists of three technologies: visual synchronisation, motion synchronisation and master-slave control. In this paper, we verify the effectiveness of the prototype system by an in vivo experiment.     

The effects of physical exercise training and cardiac education on levels of anxiety and depression in the rehabilitation of coronary artery bypass graft patients

Objective: to evaluate whether an exercise and education-based rehabilitation programme is sufficient treatment for individuals with clinically significant levels of anxiety or depression following coronary artery bypass graft (CABG) surgery. Design: follow-up and repeated assessment after surgery. Setting: outpatient cardiac rehabilitation programme. Patients: all 88 attenders after CABG surgery. Assessments: structured interview and Hospital Anxiety and Depression (HAD) scale (using 8 as the cut-off) administered by rehabilitation nurses at start of course and HAD repeated at 12 weeks and 6 and 12 months (by post after discharge). Results: return rates of 76 and 80% at 6- and 12-month assessments, respectively; statistically significant reductions in levels of anxiety and depression found between first and all subsequent assessments; subdividing into groups revealed significant reduction in anxiety and depression in the anxious and depressed groups at 12 weeks and 6 months, respectively, but at 12 months there was no significant reduction. Conclusions: there is a need to address the problems of anxiety and depression directly by screening and treatment, and to provide more psychologically-orientated cardiac rehabilitation programmes.     

实时三维牛眼征参数评价卡维地洛对高血压病心脏正常构型患者心功能的影响研究

目的应用实时三维牛眼图指标评价卡维地洛对高血压病心脏正常构型患者心功能的影响。方法选择心脏正常构型高血压病患者62例,口服卡维地洛,监测其血压的变化,分别于用药前和用药6个月后行超声检查,将图像储存于QLAB工作站,计算实时三维牛眼图参数:测量左室轴向运动最大距离(E max)、最小距离(E min)、平均距离的标准差(ESD)、轴向运动的平均距离所需时间占R-R间期平均百分比(E%);以及比较治疗前后的局部射血分数(REF)、左室射血分数(LVEF)。结果卡维地洛可以有效降低血压,治疗后E max、E min和ESD分别与治疗前比较,均明显增加,差异均有统计学意义(均P﹤0.05);E%与治疗前比较明显缩短,差异亦有统计学意义(P﹤0.05)。治疗后REF和LVEF分别与治疗前比较均增加,但差异无统计学意义(P﹥0.05)。结论实时三维牛眼图指标能够准确评价卡维地洛对正常构型高血压病患者心脏功能的影响,此药物能对其靶器官早期干预,改善心功能,防治或延缓心室重构及高血压型心脏病的发生。     

运动性心脏肥大：AT1受体、细胞自噬和miRNAs的调节

As a mechanical and exogenous stimulus, exercise training induces cardiac physiological hypertrophy, and the cardiac structure is changed slowly, steadily and coordinately. Simultaneously, energy metabolism and function of the cardiac muscle are also improved. These are positive adaptations in the heart when experiencing endurance exercise training. Recently, angiotensin Ⅱ type 1 (AT1) receptor, autophagy and miRNAs are all considered as important regulators to cardiac hypertrophy induced by exercise training at different molecular levels. Fully understanding the relations and the important role of AT1 receptor, autophagy and miRNAs in cardiac physiological hypertrophy will further enrich the signaling pathway of cardiac hypertrophy induced by exercise training.     

Quantitative assessment of left ventricular function with dual-source CT in comparison to cardiac magnetic resonance imaging: initial findings

Cardiac magnetic resonance imaging and echocardiography are currently regarded as standard modalities for the quantification of left ventricular volumes and ejection fraction. With the recent introduction of dual-source computedtomography (DSCT), the increased temporal resolution of 83 ms should also improve the assessment of cardiac function in CT. The aim of this study was to evaluate the accuracy of DSCT in the assessment of left ventricular functional parameters with cardiac magnetic resonance imaging (MRI) as standard of reference. Fifteen patients (two female, 13 male; mean age 50.8 ± 19.2 years) underwent CT and MRI examinations on a DSCT (Somatom Definition; Siemens Medical Solutions, Forchheim, Germany) and a 3.0-Tesla MR scanner (Magnetom Trio; Siemens Medical Solutions), respectively. Multiphase axial CT images were analysed with a semiautomatic region growing algorithms (Syngo Circulation; Siemens Medical Solutions) by two independent blinded observers. In MRI, dynamic cine loops of short axis slices were evaluated with semiautomatic contour detection software (ARGUS; Siemens Medical Solutions) independently by two readers. End-systolic volume (ESV), end-diastolic volume (EDV), ejection fraction (EF) and stroke volume (SV) were determined for both modalities, and correlation coefficient, systematic error, limits of agreement and inter-observer variability were assessed. In DSCT, EDV and ESV were 135.8 ± 41.9 ml and 54.9 ± 29.6 ml, respectively, compared with 132.1 ± 40.8 ml EDV and 57.6 ± 27.3 ml ESV in MRI. Thus, EDV was overestimated by 3.7 ml (limits of agreement −46.1/+53.6), while ESV was underestimated by 2.6 ml (−36.6/+31.4). Mean EF was 61.6 ± 12.4% in DSCT and 57.9 ± 9.0% in MRI, resulting in an overestimation of EF by 3.8% with limits of agreement at −14.7 and +22.2%. Rank correlation rho values were 0.81 for EDV (P = 0.0024), 0.79 for ESV (P = 0.0031) and 0.64 for EF (P = 0.0168). The kappa value of inter-observer variability were amounted to 0.85 for EDV, ESV and EF. DSCT offers the possibility to quantify left ventricular function from coronary CT angiography datasets with sufficient diagnostic accuracy, adding to the value of the modality in a comprehensive cardiac assessment. The observed differences in the measured values may be due to different post-processing methods and physiological reactions to contrast material injection without beta-blocker medication. S. Busch and T. Johnson contributed equally to this study.     

Time course of reversed cardiac remodeling after pulmonary endarterectomy in patients with chronic pulmonary thromboembolism

To evaluate the time course of reversed remodeling after pulmonary endarterectomy (PEA) in patients with chronic thromboembolic pulmonary hypertension(CTPEH), we studied 22 patients (age: 60 ± 13 years) with MRI immediately before, 1 month, 3 months, and 6 months after PEA. MRI included assessment of biventricular function, aortic and pulmonary artery(PA) flow, and right ventricular (RV) overload using the ratio of RV-to-biventricular diameter. Except in one patient, who died 2 months post-surgery, clinical improvement occurred early after PEA (NYHA class: 3.3 ± 0.6 to 1.5 ± 0.8, p < 0.0001) with a decrease of systolic pulmonary artery pressures (79 ± 14 to 44 ± 14 mmHg, p < 0.0001). At 1 month post PEA, RV end-diastolic volumes decreased (198 ± 72 to 137 ± 59 ml, p < 0.0001), and the RV ejection fraction (EF) improved (31 ± 9 to 47 ± 10%, p < 0.0001). No further significant improvement in pulmonary pressures or RV function occurred at 3 months or 6 months. Although no significant change was found in LV volumes or function, aortic flow increased early after surgery. PEA had only a beneficial effect on right PA flow. RV overload decreased early after PEA (ratio RV-to-biventricular diameter: before: 0.67 ± 0.04, after: 0.54 ± 0.06, p < 0.0001), showing a good correlation with the improvement in RVEF (r = 0.7, P < 0.0001). In conclusion, reversed cardiac remodeling occurs early after PEA, to slow down after 1 month. At 6 months, cardiac remodeling is incomplete as witnessed by low-normal RV function and residually elevated PA pressures.     

同种异体心脏移植中供体特异输注对肿瘤坏死因子-α的影响

目的　通过术前 2 4h特异输注与环孢酶素A(CsA)联合应用研究其对肿瘤坏死因子 α(TNF α)的影响。方法　将小鼠随机分组为CsA/红细胞 ,CsA/全血 ,以及红细胞 ,周围淋巴细胞 ,全血 ,低剂量CsA ,空白对照磷酸盐缓冲液 (PBS)组。术前给予相应的供体特输注 (DST) ,空白对照组注射PBS液。心脏移植方法采用耳后方法 ,实验终止后用放射免疫方法测定受体血清中的TNF α。结果　单独DST组 ,低剂量CsA组和空白对照液组之间的TNF α含量差异无显著性(P >0 .0 5 )。CsA/DST组的含量明显低于低剂量CsA组 ,空白对照PBS组和DST组 (P <0 .0 1) ,其中CsA/周围淋巴细胞组中TNF α含量为最低 2 .3 9± 0 .49(P <0 .0 1)。结论　术前 2 4h单独输注DST并不能降低受体血清中TNF α的含量 ,然而DST和CsA联合应用可以降低受体血清中的TNF α含量 ,其中以周围淋巴细胞和CsA联合应用效果最佳。