影响正常人和心肌梗塞患者等长收缩运动心血管反应的主要因素

对正常青年和中老年人，以及心肌梗塞患者进行观察，从 多方面综合评价影响等长收缩心血管反应的因素，论证了影响正常人和心肌梗塞患者心率，血压和心肌耗氧反应的基本特征和影响因素，从而为心血管患者日常生活活动和运动锻炼时处理等长收缩性活动提供指导。     

冠心病患者等长收缩运动与心肌缺血的关系

目的　探讨冠心病患者等长收缩运动与心肌缺血的关系。方法　采用超声多普勒技术 ,比较 2 0例冠心病患者和 10例正常人极量短暂等长收缩运动 (briefisometricexercise ,BIE)、极量持续等长收缩运动(sustainedisometricexercise ,SIE)与动力性运动 (dynamicexercise ,DE)时的血流动力学反应和心功能表现。 结果　有心肌缺血的冠心病患者在DE运动终点时有心肌缺血表现 ,但BIE和SIE时无相应表现。心血管反应总体趋势为 :DE时心率和两项乘积运动增量均明显高于BIE和SIE ,各组间差异不显著。正常组DE时血流动力学多数指标的运动增量均高于BIE和SIE ,但有无心肌缺血的冠心病患者之间无明显差异。结论　在同等主观用力的前提下 ,冠心病患者等长收缩运动时心肌缺血发生率低于动力性运动。等长收缩运动时较高的舒张压和较长的灌注时间对心肌缺血有一定的保护作用。等长收缩运动在冠心病康复中的应用有合理的生理学基础。     

等长运动训练降低静息血压

<正> 最近的几项研究表明,抗阻训练同节律性运动一样也可降低静息血压,且几乎不影响最大耗氧量(VO_2_(max))。但由于抗阻训练是由等长运动和节律性运动共同组成的,因此,逻辑上应对单纯等长收缩运动时血压的反应进行研究。本研究的目的就是为了评价等长收缩性握力训练对静息血压的影响。资料与方法第1组研究①对象:健康人20名,年龄20～35岁,静息舒张压10.8～12.1kPa。随机分成运功训练组和非运动对照组,每组     

血浆内源性阿片肽对冠心病患者等长收缩运动心血管反应的调控

目的：探讨血浆内源性阿片肽（ＥＯＰｓ）对等长收缩运动（ＩＥ）心血管反应的调控机制及其与心肌缺血的关系。方法：冠心病人运动试验阴性组（ＥＳＮ组,１０名）和运动试验阳性组（ＥＳＰ组,１０名）,以及正常人（ＮＯＲ组,１０名）进行最大短暂等长收缩运动（ＢＩＥ）、最大持续等长收缩运动（ＳＩＥ）及分级卧位踏车运动（ＤＥ）,观察ＥＯＰｓ变化及心血管反应。结果：从总体上ＥＯＰｓ运动反应表现为ＳＩＥ＞ＢＩＥ＞ＤＥ;各阶段各组间ＥＯＰｓ反应的趋势相似。正常人心率、血压、两项乘积、射血分数（ＥＦ）、短轴缩短率（ＳＦ）和Ｅ／Ａ表现为ＤＥ＞ＳＩＥ＞ＢＩＥ。结论：冠心病人ＩＥ的血浆ＥＯＰｓ反应与正常人类似;ＩＥ的血浆ＥＯＰｓ释放与心肌缺血无直接关联;ＩＥ,尤其是ＳＩＥ时中枢命令较强,血浆ＥＯＰｓ释放较多,可能有助于降低交感神经兴奋性,减少冠心病人的运动风险。     

高血压患者等长收缩合并乏氏动作时中心血流动力学变化

高血压患者等长收缩合并乏氏动作时中心血流动力学变化杨英霞１蒋小毛１林敏芬１郑兰君１由于长期以来医学界普遍认为肌肉的力量训练可能加剧心血管的不良反应，所以对高血压病或冠心病患者多采用长时间、大肌群、低阻抗性运动，即有氧训练，如慢跑、步行、骑车等〔１〕。...     

等张运动与等长运动相结合的康复方案对高血压患者血压及血浆内皮素的影响

目的:探讨高血压运动处方中采用等张运动与等长运动相结合的练习方法的可行性,并比较等张运动与等长运动对高血压患者的血压及血浆内皮素的影响。方法押于2003-08/2004-09随机选取邵阳学院运动康复中心高血压俱乐部老年原发性高血压患者,通过预实验筛选45例为观察对象并随机分成3组,等张训练组,等长训练组,等长+等张训练组,每组15例,各组主要基线资料具有可比性。等张训练组,等长训练组,等长+等张训练组分别制定个体化的运动处方,同时进行心电监护和全程血压监控,采用相同的靶心率和相同的运动时间,观察康复训练16周后观察对象的血压及血浆内皮素的变化。结果:单纯的等张训练和单纯的等长训练均能使观察对象的收缩压、舒张压和血浆内皮素显著降低;但对于观察对象的脉压差的影响在训练前后没有显著性的差异(P>0.05);而等张训练与等长训练相结合的综合训练方案使观察对象在训练后的收缩压、舒张压、脉压差及血浆内皮素都显著下降(P<0.01)。结论:等长运动与等张运动相结合的全面康复训练的方案可以产生良好的心血管反应,降低高血压患者的血浆内皮素水平,是高血压病运动处方的首选。     

冠心病患者等长收缩运动时肺毛细血管嵌顿压升高的机理

用左右心导管观察10例典型劳力性心绞痛患者在极量等长收缩运动(IE)和IE加乏氏动作时的血液动力学反应及临床表现,并以冠状动脉气囊扩张成形术建立急、慢性冠状动脉供血不足以及正常冠状动脉的模型。结果表明进行极量前臂等长收缩运动和乏氏动作时肺毛细血管嵌顿压升高,其机理可能与胸腔内压的增高和主动脉压的增高有关而与心肌缺血无关。这解释了为何等长收缩运动试验的敏感性不高,也说明对心脏患者禁止IE和乏氏动作的概念应该加以修正。     

大脑行为对等长收缩运动时心血管反应的调控作用与机制

目的：研究大脑行为修正对等长收缩运动（ＩＥ）心血管反应的调控及机制。方法：用气功入静作为大脑行为修正的模式,记录常态及入静态站桩（ＩＥ）时的心血管反应;用ＲＩＡ法测定血浆内源性啡肽类物质－亮氨酸脑啡肽、β－内啡肽、强啡肽的含量。结果：入静ＩＥ较常态ＩＥ心率、血压显著降低（Ｐ〈０．０１）,而血浆内源性啡肽类物质含量显著升高。结论：大脑行为可调节等长收缩时的心血管反应,与血浆血浆内源性啡肽类物质的调控     

等张运动与等长运动相结合的康复方案对高血压患者血压及血浆内皮素的影响

目的：探讨高血压运动处方中采用等张运动与等长运动相结合的练习方法的可行性，并比较等张运动与等长运动对高血压患者的血压及血浆内皮素的影响。方法：于2003-08/2004-09随机选取邵阳学院运动康复中心高血压俱乐部老年原发性高血压患者，通过预实验筛选45洌为观察对象并随机分成3组，等张训练组，等长训练组，等长＋等张训练组，每组15例，各组主要基线资料具有可比性。等张训练组，等长训练组，等长＋等张训练组分别制定个体化的运动处方，同时进行心电监护和全程血压监控，采用相同的靶心率和相同的运动时间，观察康复训练16周后观察对象的血压及血浆内皮素的变化。结果：单纯的等张训练和单纯的等长训练均能使观察对象的收缩压、舒张压和血浆内皮素显著降低；但对于观察对象的脉压差的影响在训练前后没有显著性的差异（P〉0．05）；而等张训练与等长训练相结合的综合训练方案使观察对象在训练后的收缩压、舒张压、脉压差及血浆内皮素都显著下降（P〈0．01）。结论：等长运动与等张运动相结合的全面康复训练的方案可以产生良好的心血管反应，降低高血压患者的血浆内皮素水平，是高血压病运动处方的首诜。     

正常青年、中年、老年人静态等长垂直提升运动时的心血管反应

<正> 等长肌肉收缩在体育锻炼和训练中常常被采用。据认为,由于这种试验可导致老年人不适血压反应,故对老年人有潜在危险。除了代谢速度加快之外,当肌肉收缩力超过最大自主收缩的25～30%时,血压会大幅度上升,从而加重左室负荷,导致心肌代谢需求的增加。正常心血管对静态肌肉收缩的反     

Tachycardia and coronary blood flow: non-invasive estimation during Valsalva manoeuvre and exercise

Summary. Simultaneous changes in cycle length and coronary blood flow were studied during Valsalva manoeuvre and supine cycloergometer exercise test in 10 male patients (mean age 4812 years) who had successfully undergone myocardial revascularization by surgical anastomosis of the left internal mammary artery on the left anterior descending coronary artery. Blood velocity curves in the left internal mammary artery were obtained by a non-invasive continuous-wave Doppler probe at rest, in the last phase of the expiratory effort of the Valsalva manoeuvre and at the maximum load attained during the exercise test. Mean arterial pressure by sphygmomanometer, and cardiac cycle length on the basis of Doppler recording were measured. Mean blood velocity, the length of the blood column entering the coronary bed at each cycle (cardiac cycle times mean velocity), an index of blood cell acceleration (the ratio of mean velocity to cardiac cycle), and an index of coronary resistance (the ratio of mean pressure to mean velocity), were calculated. For approximately the same change in cycle length, coronary resistance decreased in exercise, with an increased mean velocity, but increased in Valsalva, with no changes in mean velocity. The length of the blood column entering the coronary bed at each cycle was unchanged in exercise, with a marked increase in the acceleration index, while it decreased in Valsalva. Therefore, we hypothesize that tachycardia has a limiting effect on sympathetic coronary constriction in Valsalva when cardiac external work is decreased, and an additional vasodilatory effect on coronary bed in exercise when external work is increased.,     

分级等长运动对心肌梗塞心功能的影响

为指导心肌梗塞患进行等长运动，对18例心肌梗塞1月后的患进行分级等长运动，即使用最大握力的20％，40％和50％，在运动前和运动时各阶段用多普勒超声心电图测定左心室舒张和收缩功能指标。结果在20％阶段，患未出现心功能异常，40%阶段出现部分心功能指标异常，在50％阶段全部功能指标均异常，部分患出现心电图ST段缺血性压低。作否认了以往对心肌梗塞患禁忌等长运动的观点，叉不赞成无节制的进行任意的等长运动，最好在心功能检测下指导等长运动。     

Systolic and diastolic changes in human coronary blood flow during Valsalva manoeuvre

Valsalva manoeuvre is reported to be sometimes successful for the relief of angina pectoris. The present study investigated how haemodynamic changes produced by Valsalva manoeuvre can interact to improve the relationship between cardiac work and coronary blood flow. Ten male subjects aged 53 ± 12 years (SD) were considered. Blood velocity in the internal mammary artery, previously anastomosed to the left descending coronary artery, was studied with Doppler technique. The subjects performed Valsalva manoeuvres by expiring into a tube connected to a mercury manometer, to develop a pressure of 40 mmHg. The arterial blood pressure curve was continuously monitored with a Finapres device from a finger of the left hand. During expiratory effort, an increase in heart rate and a decrease in arterial pulse pressure were followed by a more delayed and progressive increase in mean and diastolic pressures. Systolic blood velocity markedly decreased along with the reduction in pulse pressure and increase in heart rate. By contrast, diastolic and mean coronary blood velocities did not show any significant change. Since it is known that the Valsalva manoeuvre strongly reduces stroke volume and cardiac output, it is likely that a reduction in cardiac work also takes place. Since in diastole, i.e. when the myocardial wall is better perfused, coronary blood velocity did not show any significant reduction, it is likely that unchanged perfusion in the presence of reduced cardiac work is responsible for the relief from angina sometimes observed during Valsalva manoeuvre. It is also likely that the increase in heart rate prevents the diastolic and mean blood coronary velocity from decreasing during the expiratory strain, when an increased sympathetic discharge could cause vasoconstriction through the stimulation of the coronary α‐receptors.     

Diagnostic and prognostic value of exercise electrocardiography for coronary artery disease

A positive exercise ECG with greater than or equal to 1.0 mm ischemic ST-segment depression, limited exercise duration, persistence of ischemic ST-segment depression past 8 minutes in the recovery period, and exertional hypotension is associated with increasing severity and extent of CAD. The sensitivity and specificity of the exercise ECG are not dependent on the prevalence of CAD in the population tested. The positive and negative predictive values of the exercise ECG are both dependent on the prevalence of CAD in the population tested. Exercise-induced ST-segment elevation greater than or equal to 1.0 mm is associated with severe myocardial ischemia, left ventricular aneurysm, left ventricular wall motion abnormalities, and coronary artery spasm in patients with variant angina. Ischemic ST-segment depression greater than or equal to 1.0 mm, exercise duration, maximal exercise heart rate, and blood pressure response to exercise are correlated with new coronary events in patients with documented CAD. Low-level exercise tests within 3 weeks of uncomplicated MI can identify patients at high risk for new cardiac events. Early post-MI patients with exercise-induced ischemic ST-segment depression greater than or equal to 1.0 mm, exercise-induced angina, an inadequate blood pressure response to exercise, or limited exercise duration during a low-level exercise test should undergo coronary angiography and be considered for possible coronary artery surgery or angioplasty. Exercise testing will also help in the medical treatment of patients with exercise-induced angina or malignant ventricular arrhythmias. An exercise test performed 6 months after MI also provides prognostic information not available from clinical evaluation.(ABSTRACT TRUNCATED AT 250 WORDS)     

Diastolic response during dobutamine stress echocardiography evaluated by a tissue velocity imaging technique is a sensitive indicator for diagnosing coronary artery disease.

BACKGROUND: Tissue velocity imaging (TVI) is a new method that measures regional myocardial velocities on the basis of color Doppler myocardial imaging principles. METHODS: To diagnose coronary artery disease (CAD) objectively by evaluating left ventricular diastolic responses during dobutamine stress echocardiography (DSE) with TVI, we performed DSE in 22 healthy participants and 28 patients with angina pectoris without wall-motion abnormality at rest. Before and during DSE, we measured the differences of time intervals from the R wave on electrocardiogram to the peak of early diastolic myocardial velocity in the same cardiac cycle between basal segments and midsegments in the septal (dT-S) and inferior (dT-I) walls by TVI. RESULTS: During DSE, dT-S in patients with left anterior descending CAD and dT-I in patients with right CAD were prolonged compared with that in healthy participants (both P <.01). The localization of the segments with a dT-S or dT-I during low-dose (10 microg/kg/min) dobutamine infusion of >32 milliseconds allowed the correct identification of the stenosed vessel in 87% of 23 patients for whom DSE was performed with the TVI technique before coronary angiography. CONCLUSIONS: The analysis of regional left ventricular diastolic responses to dobutamine stress using TVI was useful for the objective diagnosis of CAD.     

Assessment of skeletal muscle fatigue in men with coronary artery disease using surface electromyography during isometric contraction of quadriceps muscles

OBJECTIVE: To evaluate whether using surface electromyography to assess skeletal muscle fatigue during an isometric exercise has the potential to be clinically useful in patients with coronary artery disease (CAD). DESIGN: Double sample comparative study. SETTING: Cardiac rehabilitation service in France. PARTICIPANTS: Sixteen men with documented CAD and 9 age-matched healthy men. INTERVENTIONS: Assessment of quadriceps skeletal muscle fatigue on an isokinetic apparatus with surface electromyography measurements and a symptom-limited exercise test in a laboratory. MAIN OUTCOME MEASURES: The maximal voluntary isometric force (MVIF) of the quadriceps was quantified as a measure of muscle strength and isometric endurance was defined as the time required to sustain a contraction at 50% of MVIF until exhaustion. Surface electromyography signals were recorded from the vastus lateralis, rectus femoris, and vastus medialis during isometric endurance. The root mean square (RMS) and the median frequency (MF) were directly calculated on a computer and then normalized (as a percentage of the initial value). RESULTS: Muscle strength did not differ significantly between the patients with CAD and the healthy subjects (229+/-21N/m vs 228+/-52N/m), but isometric endurance was reduced (64+/-17s vs 90+/-7s, P <.01). The RMS values showed a significantly higher increase in the healthy subjects versus the patients with CAD for the vastus lateralis and vastus medialis ( P <.001). The MF values were significantly lower for the vastus lateralis, rectus femoris ( P <.01), and vastus medialis ( P <.05) in patients with CAD compared with the healthy subjects. CONCLUSIONS: Skeletal muscle fatigue occurs sooner in men with CAD relative to matched healthy men, despite similar muscle strength. This finding may be the result of an abnormality of skeletal muscle function and may play an important role in measuring functional capacity. In addition, it may be a useful tool to assess the efficacy of cardiac rehabilitation interventions.     

Doppler-derived aortic flow measurements during and after heavy isometric exercise in healthy men versus men with myocardial infarction.

Doppler echocardiography is a useful noninvasive determination of left ventricular function during dynamic exercise. Scarce data are available for the use of this technique during heavy isometric exercise. Therefore, Doppler-derived aortic flow indexes were assessed during and after 50% maximal upper-body isometric exercise in 25 healthy men (aged 47 +/- 6 years) and compared with those of 22 men (aged 48 +/- 9 years) who had suffered myocardial infarction. The heart rate increased (p = 0.01) in each of the groups from a mean of 68 +/- 12 at rest to 84 +/- 11 during isometric exercise. At rest, systolic blood pressure was higher (p = 0.05) in the patients with coronary artery disease. During exercise, the patients with cardiac disease, compared with the healthy volunteers, demonstrated a lesser reduction in flow velocity integral, stroke volume, and cardiac indexes (p = 0.001). Immediately on recovery, the patients with cardiac disease, compared with the healthy group, showed significantly greater (p = 0.001) increase in stroke volume and cardiac indexes. At 3 minute's recovery, the stroke volume index continued to increase in the patients with cardiac disease, while the healthy group showed a decrease to below its resting value. Although 50% of maximal upper-body isometric exercise caused similar heart rate and systolic blood pressure responses in healthy patients and patients with cardiac disease, there were significant group differences in Doppler-derived left ventricular systolic function indexes, which were greatest on immediate and 3 minute's recovery. The results suggest that this novel isometric test may be useful in clinical testing.     

Erectile dysfunction and silent coronary artery disease: abnormal computed tomography coronary angiogram in the presence of normal exercise ECGs

Background: Erectile dysfunction (ED) and coronary artery disease (CAD) frequently coexist. ED may be present in the absence of cardiac symptoms 3–5 years before a coronary event. Exercise electrocardiography may identify flow‐limiting CAD but cardiac computed tomography (CT) may identify early non‐calcified plaque disease potentially vulnerable to rupture precipitating an acute event. Methods: Twenty men aged 39–69 years with ED and no cardiac symptoms underwent screening for cardiovascular risk including maximal treadmill exercise testing and CT coronary angiography. ED was confirmed using the Sexual Health Inventory for Men questionnaire. Findings: Eighteen had a low‐density lipoprotein cholesterol > 3 mmol/l, none were diabetic and seven were hypertensive controlled on medical therapy. Coronary calcium scores were > 50 in 11 men (range: 54–1234) all of whom had angiographic CAD on CT. Nine of these had normal exercise ECGs. Four men had calcium scores of 6–17 and single plaque disease on CT. Five had normal cardiac CT studies. Interpretation: Erectile dysfunction may be a predictor of subclinical non‐flow limiting CAD not detectable on exercise electrocardiography. Men with organic ED and no cardiac symptoms should be considered as ‘cardiac equivalents’ and aggressive risk reduction therapy initiated.