21 d头低位卧床期间心功能的改变

目的：航天飞行时产生的失重环境可引起体液头向分布，继而引起心血管功能失调，主要表现为返回地球1G重力环境后立位耐力降低，严重者出现晕厥前症状或晕厥。目前对失重飞行致心血管功能失调的机制尚未完全阐明。头低位一6。卧床是目前应用最广泛的一种地面人体模拟失重的方法。本研究通过观察21d头低位卧床模拟失重人体心功能的变化，旨在进一步探讨失重致立位耐力不良的机制。     

30 d头低位卧床期间体育锻炼对立位耐力、运动耐力和心率变异性的影响

目的:观察和比较30 d -6°头低位卧床期间下肢肌力训练和自行车功量计训练对立位耐力、最大运动时间、体质量以及心率变异性（HRV）的影响,旨在进一步明确体育锻炼方法对失重所致心血管失调的对抗效果,为制定我国载人航天飞行时航天员失重对抗方案提供实验依据。方法:15名男性健康被试者,随机分为对照组、下肢肌力训练组和自行车功量计训练组3组,每组5人。对照组仅-6°头低位卧床30 d,不进行任何处理,下肢肌力训练组和自行车功量计训练组在30 d卧床期间分别进行下肢肌力训练和自行车功量计训练。实验前后测量立位耐力、最大运动时间,实验期间测量体质量及HRV。结果:卧床30 d,对照组的立位耐力较卧床前显著降低（P<0.01）,而下肢肌力训练组和自行车功量计训练组的立位耐力较卧床前有所降低,但未达到显著水平。卧床第30 d,对照组和下肢肌力训练组的最大运动时间较卧床前显著降低（P<0.05）,而自行车功量计训练组较卧床前无明显变化,且较对照组和下肢肌力训练组显著升高（P<0.05）。卧床期间,对照组体质量较卧床前有降低趋势,下肢肌力训练组有升高趋势,自行车功量计训练组无明显变化;卧床第10 d,下肢肌力训练组体质量较对照组显著增加（P<0.05）。HRV分析发现,卧床期间对照组归一化低频（LFn）、低频功率与高频功率的比值（LF/HF）较卧床前有升高趋势,归一化高频（HFn）有降低趋势,两锻炼组上述指标变化与对照组相似。结论:30 d头低位卧床可引起立位耐力和运动耐力显著降低,心血管自主神经调节均衡性发生改变。下肢肌力训练在一定程度上能够提高模拟失重后的立位耐力,而自行车功量计训练可提高模拟失重后的立位耐力和运动耐力。     

老年腹腔镜头低位手术患者脑氧饱和度的变化

目的探讨老年患者腹腔镜头低位手术脑氧饱和度(SctO_2)的变化。方法选择妇科及直肠腹腔镜手术患者20例,年龄≥60岁同期选择行腹腔镜头低位手术年龄60岁的患者20例为对照组。麻醉方法为气管插管全身麻醉,应用FORESIGHT近红外光仪监测SctO_2,收集入室时(TO),面罩吸氧后(T1)的SctO_2值气腹前(T2)和气腹30 min(T3)的SctO_2、动脉氧分压(PaO_2)、动脉二氧化碳分压(PaCO_2)、呼气末二氧化碳分压(PetCO_2)、平均动脉压(MAP)。结果 SctO_2在实验组T3时较T2时增高(P0.05);两组患者PaCO_2及PetCO_2在T3时均较T2时显著升高(P0.05);实验组MAP在T3时较T2时明显增高(P0.05)。结论腹腔镜头低位手术30 min内对老年及非老年患者SctO_2无明显影响。     

左束支区域起搏与右心室低位间隔部起搏对永久性心脏起搏器植入术患者心功能影响的对比研究

背景 目前希氏束起搏(HBP)被公认为是最符合生理要求的起搏方式,但其阈值高、电池寿命短,适应证严格,存在一定局限性,因此探寻更理想的符合生理性起搏的起搏方式具有重大意义.目的 比较左束支区域起搏(LBBP)与右心室低位间隔部起搏对永久性心脏起搏器植入术患者心功能的影响,以为LBBP作为更为理想的生理性起搏方式提供依据...     

充血性心力衰竭患者血清甲状腺激素和心功能的变化

测定56例充血性心力衰竭患者甲状腺激素水平的变化，发现三碘甲状腺原氨酸明显低于正常，反三碘甲状腺原氨酸显著升高。心力衰竭（心衰）程度越重，变化越明显。提示甲状腺激素变化对心衰患者心功能损害程度、治疗和预后具有一定意义。     

扩张性心肌病伴高血压患者心功能及预后的变化

目的观察扩张性心肌病患者伴有高血压与不伴高血压者临床特征的差异。方法对我院1989年至2006年155例诊断扩张性心肌病的住院病例的临床资料进行回顾性分析。结果(1)扩张性心肌病伴高血压的患者出现心力衰竭后血压高于140/90 mm Hg者占30%。(2)伴高血压的扩张性心肌病组左心室后壁厚度(LVPW)、室间隔厚度(IVS)、左心室射血分数(LVEF)、左心室心肌重量(LVMW)等各指标高于无高血压组。(3)治疗后伴有高血压组心功能改善更明显。结论(1)利用血压水平作为排除高血压所引起的心脏损害的标准有一定的局限性。(2)少部分伴高血压的扩张性心肌病可能由于高血压病史不详而属于高血压引起的心脏损害的范畴。     

先天性心脏病患儿术后心功能和氧代谢变化及意义

对50例室间隔缺损先心病患儿施行室间隔缺损修补术。麻醉方法为吸入2%七氟烷;芬太尼20μg/kg和维库溴铵0.1mg/kg行麻醉诱导及气管插管,行桡动脉穿刺直接动脉测压,右侧颈内静脉穿刺放置Swan-Ganz导管以监测心排血指数（CI）、每搏指数（SI）,同时行血气分析,计算出全身氧供指数（DO2I）、氧耗指数（VO2I）。结果术后第1、2天CO、CI均较术终显著性降低（P均〈0.05）,第3天缓慢回升;术后DO2I第1、2天较术终显著降低（P〈0.01、0.05）,第3天缓慢回升至正常。VO2I于术后第1天下降,而后升高并超出术终水平,但无统计学差异。提示先心病患儿心脏术后短期内心功能下降,氧供减少并伴有氧耗增加,应加强麻醉监测。     

康宝得维对60岁以上高血压心脏病心功能及左心室重量的作用

<正> 康宝得维(国产非罗地平缓释片)是长效钙桔抗剂,降血压效果明显.本文就60岁以上高血压病合并左心室肥大103例,用康宝得维治疗进行分析,发现其除有较好的降压作用外,还有较好的改善心脏功能和使左心室肥大退缩作用.1 对象及方法自1996年6月至1999年6月共3年103例,我院心血管专科门诊及住院高血压病Ⅱ、Ⅲ期患者103例,其中男性66例,女性37例,平均年龄65.6±19.3岁(60～80岁).合并冠心病心绞痛34例,脑梗塞18例.心脏“B”型超声心动图检查均有左心室肥大.高血压病史均在10年以上.心功能均在Ⅱ级以上(NYHA分级法).     

高血压患者左房结构变化与心功能和血浆心钠素的关系及意义

应用超声心动图技术和放射免疫方法测定高血压患者的左房和血浆心钠素水平，探讨高血压患者心功能不全左房结构变化与血浆心钠素水平的关系。结果：高血压患者随着心功能不全加重，左房增大越明显血浆心钠素水平增加。提示：高血压时心钠素合成与分泌的增加具有重要的调节意义，测定血浆心钠素将有助于评价高血压心功能不全的严重程度及左房异常变化的程度。     

不同心功能和肾功能慢性心力衰竭患者血红蛋白浓度的变化

目的探讨不同心功能和肾功能慢性心力衰竭患者血红蛋白浓度的变化。方法选择2009年10月至2010年12月在中国医科大学顺义医院心内科住院治疗的慢性心力衰竭患者490例为研究对象。检测入选对象的血常规、血生化等指标。心功能分级参照纽约心脏协会(NYHA)分级。结果心功能Ⅰ、Ⅱ、Ⅲ、Ⅳ级患者的血红蛋白减低发生率分别为:10%(1/10)、34.4%(86/250)、49.3%(69/140)、55.6%(50/90),差异有统计学意义(P<0.05)。心功能Ⅰ、Ⅱ、Ⅲ、Ⅳ级患者血红蛋白浓度中位数分别为132.5 g/L、128.0 g/L、119.0 g/L、112.0 g/L,不同心功能分级患者间血红蛋白浓度比较,差异有统计学意义(P<0.05)。肾功能正常的慢性心力衰竭患者的血红蛋白减低发生率低于肾功能异常的慢性心力衰竭患者,差异有统计学意义[26.6%(50/188)vs.46.4%(140/302),P<0.05]。Logistic回归分析结果显示肾功能异常(OR=1.544,95%CI:0.971～2.554)、重度心功能不全(OR=8.976,95%CI:1.059～4.075)是慢性心力衰竭患者发生血红蛋白浓度减低的危险因素。结论心功能分级增加及肾功能异常可导致慢性心力衰竭患者发生血红蛋白浓度减低。     

The effects of music on cardiac patients on bed rest

Hospitalizations that require invasive cardiac procedures or support with an intra-aortic balloon pump can be unsettling. This study was undertaken to measure the effect of a music intervention on physiologic and psychological responses of patients on bed rest due to procedural sheaths or an intra-aortic balloon pump. A randomized, two-group, pretest/post-test design was utilized to measure the effect of a 30-minute music intervention on heart rate, blood pressure, respiratory rate, skin temperature, pain perception, and mood states. One hundred forty subjects participated, 65 in the control group and 75 in the treatment group. There were no significant differences between the groups in demographic, clinical, or baseline variables, except for respiratory rate. After the music intervention, there were reductions in blood pressure, respiratory rate, and psychological distress, as measured by the Profile of Mood States (p < 0.05). Music appeared to affect selected physiologic responses and reduce psychological distress in patients on bed rest.     

The cardiac response to exercise training: Echocardiographic analysis at rest and during exercise

The effect of exercise training on left ventricular dimensions at rest and during steady state exercise was studied. Fourteen healthy sedentary students were studied with echocardiograms performed at rest and during the 3rd minute of supine bicycle exercise (300 kilopond-meters/min) before and after 14 weeks of vigorous interval bicycle training. Ventricular dimensions at end-systole and end-diastole were measured and stroke dimension and dimensional shortening (stroke dimension/end diastolic dimension) were calculated. Maximal rate, measured before training during maximal exercise testing, oxygen consumption increased 31 percent ± 6 (mean ± standard error of the mean); heart rate decreased 9 ± 3 percent at rest and 11 ± 3 percent during exercise (p < 0.05). Blood pressure was not significantly changed at rest or during exercise. Training was associated with an increase in end-diastolic dimension at rest (from 4.7 ± 0.11 to 5.0 ± 0.11 cm) (p < 0.05) with no change noted in end-systolic dimension. Stroke dimension at rest was increased (from 1.4 ± 0.05 to 1.7 ± 0.05 cm) (p < 0.05) as was dimensional shortening (0.32 + 0.01 to 0.35 ± 0.01) (p < 0.05). Exercise before and after training was associated with an increase in stroke dimension mediated by a decrease in end-systolic dimension. End-diastolic dimension remained constant and dimensional shortening increased 15 ± 6 percent.Exercise was associated with an increase in stroke volume mediated by an increase in contractility. The Frank-Starling effect was not demonstrable. Training resulted in increased stroke volume at rest mediated by enhanced preload (Frank-Starling effect) and increased dimensional shortening, unexplained by a decrease in blood pressure. Exercise after training was associated with an increase in stroke dimension and dimensional shortening from the higher value at rest. These changes are suggestive of an enhanced contractile state at rest and during exercise consequent to training.     

Effect of enalapril at rest, during tilt, static and dynamic exercise in systemic hypertension

Using the “Oxford system” for ambulatory monitoring of direct arterial blood pressure (BP), the hypotensive effect of enalapril (20 to 40 mg/day), was assessed in 15 patients with essential hypertension. BP was reduced by enalapril throughout the 24 hours of study. A within-patient comparison of corresponding mean hourly systolic and diastolic BP values showed a reduction from (p <0.05 to p <0.001) for 18 of the 24 hours. Four patients had an increase in BP during treatment with enalapril. There was a significant decrease in systolic BP in response to 60° head-up tilt. During isometric and dynamic exercise there was a smaller increase in systolic BP but a less marked effect on diastolic BP. Heart rate was unaffected either during free ambulation or during physiologic testing. The incidence of side effects was low. These results indicate that enalapril administered once daily may be an effective form of antihypertensive therapy. However, there is a group of patients who are unresponsive to treatment with converting enzyme inhibitors.     

Hemodynamic profiles at rest and during supine exercise after orthotopic cardiac transplantation

To characterize the spectrum of hemodynamic findings after orthotopic cardiac transplantation, 20 healthy heart transplant recipients with no evidence of cardiac dysfunction by noninvasive testing were studied for 1 to 51 months (mean 15) following surgery. After routine endomyocardial biopsy, right-sided heart pressures and thermodilution cardiac outputs were measured at rest (supine) and during symptom-limited, graded supine exercise. In addition, the effect of respiration on right atrial pressures and waveforms was determined at rest (supine, legs down), and after passive leg raising (volume loading). During exercise, striking increases of pulmonary artery, pulmonary artery wedge and right atrial pressures were seen. The mean pulmonary artery pressure rose 45% during the first stage of exercise (p less than 0.001) and by peak exercise it had increased 87% above resting values. The pulmonary artery wedge pressure increased significantly with passive leg elevation (p less than 0.001) and during the first stage of exercise rose 61% above baseline values. By peak exercise the mean pulmonary artery wedge pressure was more than double the resting value. Similarly, the right atrial mean pressure increased significantly (p less than 0.001) with passive leg elevation and nearly tripled at peak exercise. All values promptly returned to near baseline after exercise. The cardiac output increased 98% during exercise. During early exercise, the rise in cardiac output was mediated primarily by an increase in stroke volume. At rest, there was an abnormal response in right atrial mean pressure during slow deep inspiration in 7 individuals with legs down and in 12 after passive leg elevation (volume loading), including 4 of 10 patients studied beyond 1 year.(ABSTRACT TRUNCATED AT 250 WORDS)     

Left ventricular function at rest and during exercise in acute hypothyroidism

The effect of hypothyroidism on left ventricular function at rest and during exercise was studied in nine patients without demonstrable cardiovascular disease who had had total thyroidectomy and ablative radioiodine treatment for thyroid cancer. Radionuclide ventriculography and simultaneous right heart catheterisation were performed while the patients were hypothyroid two weeks after stopping triiodothyronine treatment (to permit routine screening for metastases) and while they were euthyroid on thyroxine replacement treatment. When the patients were hypothyroid, cardiac output, stroke volume, and end diastolic volume at rest were all lower and peripheral resistance was higher than when they were euthyroid. Pulmonary capillary wedge pressure, right atrial pressure, heart rate, left ventricular ejection fraction, and the systolic pressure:volume relation of the left ventricle, which was used as an estimate of the contractile state, were not significantly different when the patients were hypothyroid or euthyroid. During exercise, heart rate, cardiac output, end diastolic volume, and stroke volume were higher when the patients were euthyroid than when they were hypothyroid. Again, pulmonary capillary wedge pressure, ejection fraction, and the systolic pressure:volume relation were similar in both thyroid states. The data suggest that the alterations in cardiac performance seen in short term hypothyroidism are primarily related to changes in loading conditions and exercise heart rate; they do not suggest that acute thyroid hormone deficiency has a major effect on the contractile properties of the myocardium.     

Physiological effects of roflumilast at rest and during exercise in COPD

The purpose of this study was to investigate the effects of 500 μg roflumilast, taken once daily for 12 weeks, on airway physiology during rest and exercise in patients with moderate-to-severe chronic obstructive pulmonary disease. This randomised, double-blind, placebo-controlled, parallel-group study was conducted in 250 patients with a post-bronchodilator forced expiratory volume in 1 s (FEV(1)) of 30-80% predicted and a functional residual capacity of ≥ 120% pred. Pre- and post-bronchodilator spirometry and body plethysmography, and pre-bronchodilator constant work rate cycle exercise at 75% of peak work rate were evaluated. Exercise measurements included ventilation, breathing pattern, inspiratory capacity (IC) and arterial oxygen saturation measured by pulse oximetry (S(p,O(2))). Compared with placebo, 12 weeks of treatment with roflumilast was associated with: small but progressive increases in pre- and post-bronchodilator FEV(1) and FEV(1)/forced vital capacity; small decreases in specific airway resistance; and no significant changes in resting vital capacity, IC or measurements of lung hyperinflation. There was no treatment effect on exercise endurance time. At a standardised exercise time after roflumilast, compared with placebo, IC increased by 0.12 L (p = 0.008) and S(p,O(2)) increased by 0.7% (p = 0.020); peak ventilation increased by 1.9 L · min(-1) (p = 0.014). Roflumilast treatment was associated with progressive improvement of airway function but not lung hyperinflation. Newly described non-bronchodilator effects of roflumilast included small but consistent improvements in air trapping and S(p,O(2)) during exercise.