慢性心房颤动患者心室率变化意义的探讨

目的分析探讨慢性心房颤动患者心室率变化的意义，为临如何预防心房颤动患者出现脑栓塞、心功能降低等并发症提供理论依据。方法将入院或门诊就诊病程超过1年的慢性心房颤动患者分为脑栓塞组和非脑栓塞组，各30例，观察比较两组患者临床特征，动态心电图计数比较两组患者最大心室率、平均心室率及最小心室率变化，超声心动图测定两组患者左房内径大小、左室射血分数变化，血浆凝血酶原时间凝固法测定两组患者血浆凝血酶原时间国际标准化比值（INR）变化。结果两组患者一般临床特征、左房内径大小、INR值比较。差异无统计学意义。脑栓塞组最大心室率、平均心室率及最小心室率均明显快于非脑栓塞组，左室射血分数明显低于非脑栓塞组。结论慢性心房颤动患者降低心室率对预防脑栓塞、左心功能降低有重要意义。     

Mental stress-induced myocardial ischemia in coronary artery disease patients with left ventricular dysfunction

Background  Reduced left ventricular ejection fraction (LVEF) is a risk factor for poor outcomes in patients with coronary artery disease (CAD). Mental stress-induced myocardial ischemia (MSIMI) also identifies a subset of CAD patients at increased risk for future cardiovascular events. Susceptibility to MSIMI in patients with CAD and reduced LVEF is unknown. Methods and Results  We enrolled 182 patients (67 women) with a mean age of 64 years and a documented history of CAD in this study. Baseline resting ejection fraction was determined by use of technetium 99m sestamibi gated single photon emission computed tomography. Abnormal LVEF was defined as less than 45% for men and less than 50% for women (based on published norms for our software [Cedars-Sinai Medical Center]). All participants underwent mental stress testing with a public speaking task. Rest/stress myocardial perfusion single photon emission computed tomography was performed via conventional methodology. Images were visually compared for number and severity of perfusion defects by use of a scoring method from 0 to 4. A summed difference score was calculated as the difference between summed stress and rest scores. A score of greater than 3 was considered abnormal. MSIMI developed in 19% of patients with normal LVEF and 31% of those with reduced LVEF. There is no statistically significant difference between the two groups (P=.11). Conclusions  CAD patients with left ventricular dysfunction are equally susceptible to MSIMI as those with normal LVEF. This study was supported by grants HL 070265 and HL 072059 from the National Heart. Lung, and Blood Institute. This material is also the result of work supported by resources and with the use of facilities at the Department of Veterans. Affairs Medical Center, Gainesville, Fla.     

主动脉内球囊反搏在低射血分数患者非体外循环冠状动脉旁路移植术中应用的必要性探讨

目的探讨对低射血分数患者施行非体外循环冠状动脉旁路移植术(off-pump coronary artery bypass grafting, OPCAB)预防性应用主动脉内球囊反搏(intraaortic balloon pump, IABP)辅助的必要性. 方法 2001 年1 月～2004年10月对64例低射血分数(LVEF≤40%)施行OPCAB,将64例分为2组:术前或术中预防性应用IABP辅助者列为IABP组,共19例;未应用IABP者列为对照组,共45例. 结果 IABP组与对照组在术后并发症手术死亡、脑血管意外、肾功能衰竭衰血滤、围手术期心肌梗死等方面无显著差异(χ2=0.000,P=1.000).IABP组术后需要延长呼吸机带机时间(超过24 h)的比例显著高于对照组(IABP组8例,对照组3例; χ2=9.429,P=0.002);IABP组术后监护时间延长(超过48 h)的比例显著高于对照组(IABP组14例,对照组19例; χ2=4.110,P=0.043). 结论在无IABP辅助的情况下,为低射血分数患者实施OPCAB手术是可行的.     

Mortality risk associated with ejection fraction differs across resting nuclear perfusion findings

Background  Left ventricular ejection fraction (LVEF) is a significant predictor of morbidity and death. The nuclear summed rest score (SRS) measures myocardial perfusion defects and provides prognostic information, but its effects on long-term outcomes are not fully established. Moreover, information regarding the potential interaction between these 2 covariates is limited. The purpose of this study was to determine whether the mortality risk associated with LVEF is the same across all values of SRS in a population undergoing evaluation for ischemic heart disease. Methods and Results  We examined 3,187 patients who underwent cardiac catheterization and perfusion single photon emission computed tomography imaging with a maximum follow-up of 8.1 years and median follow-up of 3.1 years. Cox proportional hazards modeling showed that increasing nuclear SRS and decreasing LVEF were independently associated with a higher long-term mortality rate, with a clinically significant interaction between them (P=.032). Patients with a normal LVEF and a high SRS (greater perfusion abnormality) have a prognosis similar to those with a reduced LVEF. Conclusions  Resting perfusion studies provide prognostic information for long-term survival and significantly impact the interpretition of mortality risk associated with changes in LVEF. Patient prognostication, risk stratification, and future research using these variables should take this interaction into account. Supported by a grant from the Tom & Lynn Royster Foundation. Durham, NC, and a National Institutes of Health Research Fellowship Grant (T5 GM08679-04), Bethesda, Md.     

Growth fractions of breast cancer in relation to epidermal growth factor receptor and estrogen receptor

Growth fractions detected by a monoclonal antibody, Ki-67, were examined in 40 human breast cancer tissues and the results compared with the immunocytochemical reactivities of epidermal growth factor receptor (EGFR) and estrogen receptor (ER). The proportion of proliferating cells displaying Ki-67 positive staining was significantly higher in the EGFR positive tumors than in the EGFR negative tumors (p<0.01). The average percentage of Ki-67 positive cells in the EGFR positive tumors was 19.9 per cent, whereas that in the EGFR negative tumors was 8.0 per cent. By contrast, an inverse relationship between the proportion of proliferating cells and ER positive cells detected by anti-ER monoclonal antibody was observed. This data indicated the difference in growth fractions with relation to the EGFR and ER status of breast cancer.     

Ejection fraction by combined inverse Fourier analysis and second-derivative technique: Correlation with isocontour method

Summary In order to measure ejection fractions (EFs) from nuclear ventriculograms, we devised a semi-automated edge-detection technique based on a combination of inverse Fourier analysis and second-derivative techniques. Initial clinical studies showed that, for the left ventricle, our method gives EF values statistically identical with those obtained using a conventional isocontour technique. For the right ventricle, however, the values obtained using the two methods were somewhat more at variance. Despite requiring a longer processing time, the results obtained with our method are reproducible because less operator intervention is necessary.     

The estimation of the plasma free fraction of cyclosporine in rabbits and heart transplant patients: The application of a physiological model of renal clearance

We estimated the free fraction (f_u) of cyclosporine (CyA) in the plasma from concentrations of CyA in urine (C_u) and plasma (C_p), urine flow rate (UF), and glomerular filtration rate in rabbits and in heart transplant patients. Following intravenous administration of CyA (5–30 mg kg^?1) in ten NZW rabbits and oral administration of CyA (4.8–12.1 mg kg^?1) in nine heart transplant patients, CyA concentrations in urine and plasma were measured by HPLC. The ratios of C_u to C_p and UF data were fitted to a physiological model of renal clearance using NONMEM. The free fraction of cyclosporine in the rabbits and the heart transplant patients was 0.0122 and 0.14, respectively. Because of the relatively low permeability of CyA across the tubular epithelium, no apparent equilibrium between C_u and C_p at any urine flow rate was reached and, therefore, the C_u to C_p ratio will not be equal to f_u.     

Determination of proliferating fractions in malignant melanomas by anti-PCNA/cyclin monoclonal antibody

An immunohistochemical study of melanocytic tumours using 19A2, a monoclonal antibody against proliferating cell nuclear antigen (PCNA/cyclin), was performed on tissues routinely processed with formalin fixation and paraffin embedding. In normal skin, keratinocytes of the suprabasal region in epidermis, the papillae and outer root sheath of hair follicles and the basal cells lining the lobules of sebaceous glands were stained in the nucleus. Other skin components, including basal and follicular melanocytes, did not demonstrate nuclear labelling. In addition, expression of PCNA/cyclin in keratinocytes was higher in sun-exposed skin compared with unexposed skin. In melanocytic lesions, PCNA/cyclin positive tumour cells increased in number and staining intensity according to the following progression: common melanocytic naevi; dysplastic naevi; primary melanomas; and metastatic melanomas. Expression of PCNA/cyclin, therefore, provides a useful marker for proliferation and tumour progression in skin.     

三种粪便隐血试验的比较研究

粪便隐血试验是检测消化道微量出血的重要手段。本文用三种隐血试验:血红蛋白定量试验(HQT)、反向间接血球凝集试验(RPHA)和联苯胺试验(BT)对不同消化道疾病患者的粪便进行检测。结果表明隐血的检出用HQT和RPHA较BT更为特异和敏感。     

二维超声心动图对高原婴幼儿右室射血分数的估测

目的：将二维超声测量右室射血分数（RVEF）的方法应用于临床。方法：用心尖四腔观单平面面积－长度法测量43例高原正常婴幼儿RVEF，并与40例患右室扩张肥厚型心肌病（RVDCHM）婴幼儿进行了比较。结果：健康组RVEF均值为58．20％，标准差为7．24％；患儿组均值为36．10％，标准差为7．01％，两组测量的RVEF有非常显著差异（P＜0．001）。结论：心尖四腔观单平面面积－长度法测量RVEF可作为估测右室收缩功能的简单可靠的方法。