冠心病患者运动时左室容积及压力—容积比值变化的研究

采用放射性核素心室造影结合卧式踏车运动试验，对１５例正常人及４２例冠心病患者左室舒张末容积指数（ＥＤＶＩ）、收缩末容积指数（ＥＳＶＩ）及收缩血压／收缩末容积（Ｐ／ＥＳＶ）等血液动力学参数的运动变化进行了研究。结果，正常人运动时ＥＤＶＩ增加，ＥＳＶＩ降低；冠心病患者ＥＤＶＩ增加，ＥＳＶＩ增加。劳累性心绞痛病人ＥＤＶＩ的增加幅度明显高于正常人及陈旧性心肌梗塞病人。以Ｐ／ＥＳＶ表示左室收缩末压力－容积关     

冠心病患者运动时左室容积及压力－容积比值变化的研究

采用放射性核素心室造影结合卧式踏车运动试验，对１５例正常人及４２例冠心病患者左室舒张末容积指数（ＥＤＶＩ）、收缩末容积指数（ＥＳＶＩ）及收缩血压／收缩末容积（Ｐ／ＥＳＶ）等血液动力学参数的运动变化进行了研究．结果，正常人运动时ＥＤＶＩ增加，ＥＳＶＩ降低；冠心病患者ＥＤＶＩ增加，ＥＳＶＩ增加．劳累性心绞痛病人ＥＤＶＩ的增加幅度明显高于正常人及陈旧性心肌梗塞病人．以Ｐ／ＥＳＶ表示左室收缩末压力－容积关系，其运动变化对冠心病诊断的灵敏度为９５％，特异性９３％，准确性９５％．     

核素心室显像评估法洛四联症根治术前后心脏功能的价值

核素心室显像评估法洛四联症根治术前后心脏功能的价值陈宪英张兆中王凯庚钟希德姜红刘志凡附表法洛四联症手术前后与对照组左右心室功能参数（ｘ±ｓ）比较组别例数ＬＶＥＦ（％）ＬＰＥＲ（ＥＤＶ／ｓ）ＬＰＦＲ（ＥＤＶ／ｓ）ＲＶＥＦ（％）ＲＰＥＲ（ＥＤＶ／ｓ）ＲＰ...     

β受体阻滞剂和慢性充血性心衰的治疗

慢性充血性心衰(CHF)的代偿开始是交感神经兴奋性增加导致心动过速、增加心肌收缩力，根据Frank-Starling定律进一步导致心室腔扩大，但只是短暂的代偿，随着心室充盈压的不断增加，心室壁张力亦增加，根据Laplace定律，心室壁张力增大进一步增加心脏耗氧，持续压力及容量增加导致心脏重量增加。     

放射性核素心脏显像对SLE患者的临床应用

目的评价系统性红斑狼疮（ＳＬＥ）患者左心室功能。方法用平衡法门电路心室显像及心肌显像测定２０例正常人和３０例ＳＬＥ患者左室收缩和舒张功能。结果ＳＬＥ患者左室射血分数、相角程、高峰射血率、高峰充盈率分别为０５２±０１１、６０８９±１２１２°、３０８±０４８ＥＤＶ／ｓ和２８８±０４７ＥＤＶ／ｓ；正常对照组分别为０６８±００２、５３２５±５２６°、３６６±０５１ＥＤＶ／ｓ和３３４±０８８ＥＤＶ／ｓ。两组比较，ｔ值分别为４５０、３１１、５８０和４６０，Ｐ均＜００１。阳性率为４８６％，心肌显像阳性率为６４％；放射性核素心脏显像检测ＳＬＥ心肌损害的灵敏度为６３％，特异性为８５％。结论放射性核素心脏显像可以客观评价ＳＬＥ患者左心室功能，对发现ＳＬＥ心肌损害及指导治疗有一定意义。     

核素心室显像对法洛四联症矫正术前后心室功能的评价

为判断法洛四联症患者手术后心室功能的变化，对４３例病人分别于术前有术后２５－３５天进行放射性核不心室显像，以心室射血分数、高峰射血率、高峰充盈率作为心功能指标。结果：术前奁室射血分数（ＬＶＥＦ）、左室高峰射血率（ＬＶＰＥＲ）、左室高峰充盈率（ＬＶＰＦＲ）分别为５５％、２．９５ＥＤＶ／ｓ和３．０５ＥＤＶ／ｓ，术后分别为７１％、４．３５ＥＤＶ／ｓ和５．０５ＥＤＶ／ｓ。术前右室射血分数（ＲＶＥＦ）、右室     

左心室心肌局部缺血的生物力学模型及计算机仿真研究

目的 研究心肌局部缺血的生物力学机制,探讨局部缺血时心室不同部位心肌纤维收缩功能变化。方法 以左室外部形状、心肌纤维的空间分布方向、电信号传播和心肌力学为基础,建立了左室心肌局部缺血的时变数学模型。然后将该模型嵌入我们已有的多元循环系统模型,分别仿真研究了内、外心室壁缺血时左室收缩力变化。结果 缺血区域心肌收缩力降低,非缺血区域收缩力显著增加;与心室壁外层心肌缺血相比,内层心肌缺血时对左室收缩功能影响更大。结论 心肌局部缺血时正常心肌区域具有代偿作用,以维持心脏的正常功能;本工作建立了左室心肌局部缺血与心血管系统功能关系的模拟实验方法。     

核素心室显像相位分析检测甲亢患者心功能

相位分析以心室各部位心肌收缩的同步性、协调性反映心脏的收缩功能。本研究总结了64例甲亢患者在合并甲状腺功能亢进症（简称甲亢）性心脏病前的核素心室显像相位分析结果，探讨甲亢患者心脏功能的变化，现报道如下。     

评价心室肌收缩力的参数：Emax及其方法

通过理论分析发现心室收缩期的最大张力、心室收缩末期压力和每搏心输出量三者之间存在着相互关系，从而获得一种新的简便的评价心室肌收缩力的方法—心室收缩末期容积—压力相关直线斜率（Ｅｍａｘ）。用１２条狗进行实验验证，测得的Ｅｍａｘ值（０．６０±０．１７ｋＰａ／ｍｌ）与复杂方法测得的值相接近；而且重复性好，能非常敏感地反映出心肌收缩力的变化。结果表明，采用这种方法来评价心肌缺血时的心室肌收缩功能，比其他血流动力学参数更有效。因此，本方法是一种有效的评价心室肌收缩力的方法。     

核素心室显像对心动过速患者射频消融或手术前后的心室功能观察

为了评价射频消融（ＲＦＡ）对心室功能的影响，应用核素心室显像（ＲＮＶ）测定了３８例，３例为全并室性心动过速（ＶＴ）患者ＲＦＡ前后以及２０例正常对照者的心室功能，半自动计算左心室射血分数（ＬＶＥＦ）、右心室射心分数（ＲＶＥＦ）、１／３ＬＶＥＦ、左室高峰充盈率（ＬＶ－ＰＦＲ）、右室高峰充盈率（ＲＶ－ＰＦＲ）。结果提示：窦性心律时，对照组与病人组ＲＦＡ前、后心功能差异无显著性，而１０例Ｗ－Ｐ－Ｗ患者经食     

核心脏病学在心力衰竭中的临床应用

核心脏病学的显像技术是一种常用的无创的诊断心力衰竭的重要手段,在评估心力衰竭程度和指导心力衰竭治疗方面发挥了重要作用。定量门控SPECT心肌灌注显像借助其定量分析软件,可以定量评价心脏容积、左心室射血分数、每搏输出量、心脏舒张功能。静息和（或）负荷心肌灌注显像不仅能鉴别非缺血性心力衰竭和缺血性心力衰竭,而且能判别心肌是否存在活性。核心脏病显像技术能轻易地鉴别出舒张性心力衰竭（也称为射血分数正常的心力衰竭）,它通过高峰充盈率和高峰充盈率时间可以准确地评估舒张性心力衰竭的程度。借助三维成像等新技术定量门控SPECT能有效评估左室运动情况,评估室壁厚度对其是一个很好的补充。心肌灌注显像还常用于判别患者是否适合植入心脏除颤器及是否适合进行心脏再同步化治疗。123I-间碘苄胍神经递质显像能为心力衰竭患者提供预后信息。心肌代谢活动与其功能密切相关,能量代谢底物是评价药物治疗是否有助于提高心力衰竭患者心功能的一个指标,123I-15-(p-碘苯基)3-R,S-甲基十五烷酸是一种临床研究中常用的心肌代谢显像示踪剂。借助新示踪剂的应用,包括神经递质显像和心肌代谢显像在内的核心脏病学显像技术常用来完善心力衰竭的诊断。核心脏病学显像技术在诊断心力衰竭及指导临床治疗方面做出了巨大贡献。     

Cardiac efficiency and oxygen consumption measured with 11C-acetate PET after long-term cardiac resynchronization therapy.

Cardiac resynchronization therapy (CRT) is a treatment option in patients with severe heart failure and left bundle-branch block (LBBB). This study evaluated the effects of 4 and 13 mo of CRT on myocardial oxygen consumption (MVO2) and cardiac efficiency as compared with mild heart failure patients without LBBB. METHODS: Sixteen patients with severe heart failure and LBBB due to idiopathic cardiomyopathy were studied at baseline and after 4 and after 13 mo of therapy. Thirteen patients with mild heart failure without LBBB served as a comparison group. The clearance rate (k2) of 11C-acetate was measured with PET to assess MVO2. Stroke volume was derived from the dynamic PET data according to the Stewart-Hamilton principle and, furthermore, cardiac efficiency using the work metabolic index. RESULTS: After 4 mo of CRT, stroke volume index (SVI) increased by 50% (P = 0.012) and cardiac efficiency increased by 41% (P < 0.001). Global k2 remained unchanged but regional k2 demonstrated a more homogeneous distribution pattern. The parameters showed no significant changes during therapy. Under CRT, cardiac efficiency, SVI, and the distribution pattern of regional k2 did not differ from mild heart failure patients without LBBB. CONCLUSION: CRT improves cardiac efficiency for at least 13 mo, as demonstrated by a higher SVI, whereas MVO2 remains unchanged. Cardiac efficiency, SVI, and the MVO2 distribution pattern reach the level of patients with mild heart failure without LBBB. The unfavorable hemodynamic performance in heart failure with LBBB is effectively restored by long-term CRT to the level of an earlier disease state.     

Echocardiography and circulatory response to progressive endurance exercise

Cardiac ultrasound techniques have provided an abundance of empirical information regarding normal circulatory responses to dynamic exercise. These data are consistent with a schema by which alterations in peripheral resistance, effected by arteriolar dilatation, facilitate blood flow to exercising muscle and match these responses to increasing metabolic demand. In this model, cardiac responses are governed by quantity of systemic venous return, matched by increases in heart rate to maintain a constant ventricular filling volume. In a progressive test in the upright position, stroke volume rises early, then plateaus as work intensity rises. The initial increase in stroke volume reflects refilling of the heart from the sequestration of blood in the dependent extremities by gravity that occurs when assuming the upright position. Well documented improvements in both inotropic and lusitropic function during progressive exercise therefore serve to maintain constancy of stroke volume and ventricular filling, respectively, with progressive shortening of systolic and diastolic time periods as work intensity rises. During exercise, then, the circulatory system appears to act like an arterial venous fistula, with peripheral resistance serving as the principal factor facilitating and controlling blood flow. Observations in subjects with altered circulatory dynamics during exercise (patients with cardiac disease, highly trained endurance athletes) can be understood within the context of this physiological model.     

Resistance exercise in chronic heart failure: hemodynamic and metabolic adjustments

The aim of this study was to characterize hemodynamic and metabolic responses to dynamic resistance exercise in chronic heart failure patients (CHF) compared to healthy older men (CTR). We hypothesized that in controlled conditions; pharmacologically treated CHF should show the adaptations to the strength exercises similar to healthy subjects, demonstrating therefore the compatibility with the practical on field. We addressed the acute effects of dynamic resistance exercise in eight CHF patients and eleven age-matched CTRs, instrumented for expiratory gas and cardiovascular analysis. All subjects performed two series with up to twelve repetitions at 70 % of 1RM on a leg press machine. Arterial pressure and heart rate progressively increased throughout the movements and decreased on cessation, while stroke volume (Modelflow software) decreased by 30 % at the start and increased by 10 % at cessation. Cardiac output increased at cessation only. All values were lower in CHF, but the changes during the exercises were not significantly different from those of CTR. Oxygen consumption increased during the exercises and continued increasing thereafter up to 60–70 % V’O_2max (absolute changes were smaller in CHF). We concluded that the response to dynamic resistance exercise is characterized by a sharp hindrance to the output of blood from the heart, which reduces stroke volume and enhances arterial pressure in CHF as well as in CTR. The simultaneous increase in heart rate kept cardiac output unaltered. The most important differences concerned a reduced metabolic response during exercise in CHF, even more evident in rest. Chronic heart failure syndrome and its treatment do not interfere with the cardiovascular responses to these kinds of physical activities. This finding can be considered a step forward in demonstrating that patients with chronic heart failure can, in controlled conditions, safely practice these essential exercises to preserve their muscle integrity.     

Quantitative determination of regional extravascular lung water and regional blood volume in congestive heart failure

Regional extravascular lung water (rELW) and blood volume (rBV) in five controls and 14 patients with congestive heart failure (CHF) were measured by constant infusion of H215O and inhalation of 11CO using positron emission tomography (PET). The analysis of 18 regions per patient revealed a relatively homogeneous level of rELW in the controls (mean = 0.11 +/- 0.02 g/cc; range, 0.08-0.21), whereas this increase in patients with CHF (0.17 +/- 0.02 g/cc; range, 0.10-0.51). The rBV was 0.21 +/- 0.02 g/cc in the controls and 0.17 +/- 0.02 g/cc in patients with CHF. A good correlation was found between the severity of chronic heart failure (according to the grading of the New York Heart Association) and mean extravascular lung water (ELW) (r = 0.69), as well as between CHF and the ratio rELW/rBV (r = 0.87); however, the correlation to hemodynamic data was less satisfactory (cardiac index, r = 0.45; pulmonary capillary wedge pressure, r = 0.47; ejection fraction, r = 0.60). In supine controls, a progressive decrease in regional blood volume from the basal to the apical regions was observed, whereas the differences in ELW were only small. In patients with chronic heart failure, ELW in the basal parts was markedly increased, whereas in the apical regions, only minor deviations from the controls were observed. In the basal regions of these patients, the blood volume was reduced by about 30%. Instead of the normal basoapical gradient of blood volume, these patients showed a rather flat distribution. Radiographic findings of pulmonary edema generally appeared together with an ELW level of greater than 0.14 g/cc.(ABSTRACT TRUNCATED AT 250 WORDS)     

Reduced leg blood flow during submaximal exercise in type 2 diabetes

It is unclear whether impaired cardiac and/or vascular function contribute to exercise intolerance in patients with type 2 diabetes. PURPOSE: Magnetic resonance imaging (MRI) was used to determine whether reductions in cardiac output and/or femoral arterial blood flow contribute to reduced aerobic capacity in patients with type 2 diabetes. METHODS: Cardiac and femoral arterial blood flow MRI scans were performed at rest and during low-intensity leg exercise in eight patients with type 2 diabetes and 11 healthy individuals. Maximal aerobic capacity VO(2 max) and maximal oxygen pulse were also determined in all participants. RESULTS: V O(2 max) was 20% lower and maximal oxygen pulse was 16% lower in patients with type 2 diabetes (P < 0.05), whereas maximal heart rate was the same between groups. Low-intensity exercise induced a 20% increase in heart rate and cardiac output as well as a 60-70% increase in femoral blood flow in both groups (P < 0.05). Femoral arterial blood flow indexed to thigh lean mass was reduced during exercise in patients with type 2 diabetes compared with healthy individuals. Stroke volume indexed to fat-free mass was lower in patients with type 2 diabetes, but greater heart rate allowed cardiac output to be maintained during submaximal exercise. CONCLUSIONS: These findings suggest that impaired femoral arterial blood flow, an indirect marker of muscle perfusion, affects low-intensity exercise performance in patients with type 2 diabetes. However, because of lower exercising stroke volume, we propose that femoral arterial blood flow and, possibly, cardiac output, limit V O(2 max) in patients with type 2 diabetes.     

A pilot study on left ventricular dimensions and wall stress before and after submaximal exercise.

Left ventricle dimensions and wall stress were measured echocardiographically before and immediately after exercise in 14 athletes and 7 control subjects. Our findings suggest that afterload is an important determinant of cardiac performance and wall hypertrophy in athletes. In spite of major changes in heart rate and blood pressure, left ventricular wall stress remains unchanged following submaximal exercise, in trained and untrained hearts. It would appear that the changes in heart size during exercise are to a large extent limited in untrained ventricles, as smaller left ventricular dimensions are required, to "normalise" wall stress. This results in a lower stroke volume for a given stroke dimensional change. Consequently cardiac output is a function of heart rate rather than stroke volume in untrained subjects. The effect of increased muscle mass in athletes, is to permit larger left ventricular dimensions for a given afterload, thus stroke volume can be augmented. The increase h/R ratio suggests that afterload is more important than preload in the development of left ventricular hypertrophy in rowers and swimmers.     

多巴胺、地高辛、ACEI、呋塞米联合用治疗难治性心衰21例疗效观察

目的总结多巴胺、地高辛、ACE I、呋塞米合用治疗难治性心力衰竭的价值。方法对21例难治性心衰(心功能Ⅲ级9例,Ⅳ级12例)采用多巴胺静滴,地高辛、卡托普利或依那普利口服,呋塞米静注5~7 d,观察心功能、心脏每搏排出量(SV)、射血分数(EF)、心脏指数(C I)、心肌耗氧量变化情况。结果显效12例(57.1%),有效7例(33.3%),无效2例(9.6%);EF,SV,C I治疗后均较治疗前显著提高(P<0.01);心肌耗氧量治疗后较治疗前明显降低(P<0.01)。结论多巴胺、地高辛、ACE I、呋塞米合用治疗难治性心力衰竭,疗效佳、安全。     

Cardiopulmonary effects of volume expansion in man: radiographic manifestations

Cardiovascular and humoral responses to extremes of sodium intake (10-1500 mEq/day) were studied. Chest radiographs of eight normal men were obtained to measure changes in heart volume and central vascular structures. Echocardiographic measurements of cardiac chamber dimensions were also obtained. Sodium loading resulted in a 16-mm-Hg increase in mean arterial pressure and increases in cardiac output, stroke volume, left ventricular end-diastolic volume, and all radiographically determined cardiac dimensions. There was direct correlation between the radiographic cardiac dimensions and left ventricular end-diastolic volume. There was no echocardiographic evidence of pericardial fluid. After sodium loading, there was enlargement of the superior vena cava, innominate veins, azygos vein, pulmonary vessels, and the aortic knob. Small pleural effusions were commonly seen. Volume expansion may cause radiographic changes that may mimic those associated with congestive heart failure. This may particularly be the case in patients with renal failure, those receiving dialysis treatment, or patients receiving large volumes of intravenous fluids.     

Evaluation of 99mTc-albumin distribution ratio in the cardiac chambers and lungs

In order to assess blood volume of the cardiac chambers and lungs, distribution ratio of 99mTc-albumin (HSA) was obtained from radionuclide angiocardiogram and non-gated or gated equilibrium cardiac pool scintigram, using a scintillation camera coupled to a minicomputer. The radio-activity of 99mTc of the entire cardiac blood pool including the large vessels (T), the right ventricle including the right atrium (RV) and the left ventricle (LV) was calculated from the 30 degrees anterior oblique cardiac pool scintigram. That of the both lungs (Lu) was calculated from the anterior cardiac pool scintigram. The radioactivity of total injected dose of HSA (H) was estimated from the initial transit of the tracer obtained by the radionuclide angiocardiogram. Then, distribution ratio of HSA of the each region of interest was expressed as RV/H, LV/H, T/H and Lu/H. RV/H, LV/H and T/H were 3.4 +/- 0.6%, 3.1 +/- 0.5% and 10.4 +/- 2.0% in controls, 6.0 +/- 0.8%, 2.6 +/- 0.8% and 14.2 +/- 2.4% in cor pulmonale, and 7.9 +/- 1.7%, 7.7 +/- 3.5% and 20.7 +/- 4.3% in heart diseases with left heart failure, respectively. Lu/H was 4.9 +/- 1.4% in controls, 4.4 +/- 1.1% in cor pulmonale and 6.6 +/- 1.9% in heart diseases without left heart failure. LV/H was correlated with left ventricular end-diastolic volume by contrast ventriculography. LV/H and RV/H were related with functional classification of NYHA. In conclusion, these parameters may be utilized as indices of the volume of blood pool of the heart chambers and lungs, and this method seems to be clinically applicable for the evaluation of pathophysiology in heart diseases.