心电运动试验的ST-V现象

目的研究心电分级运动试验出现的ＳＴ段下移一过性好转的现象。方法对１０００例中老年人进行症状限制性心电分级运动试验（Ｂｒｕｃｅ方案）。结果２３％的对象运动后即刻至２分钟时出现ＳＴ段下移一过性好转的现象,呈“Ｖ”形变化曲线,称之为ＳＴＶ现象。ＳＴＶ现象的阳性率在可疑ＣＡＤ运动试验阳性者达５０％,在体检运动试验阳性者达３４％。结论ＳＴＶ现象是心电运动试验中的常见情况,其相关因素包括：运动试验阳性、年长、运动能力较差、运动中和运动后收缩期血压反应较强烈,该现象的机理和临床意义值得进一步研讨。     

Comparison of stroke volume estimation for non-steady-state and steady-state graded exercise testing

The stroke volume (SV) during exercise is an important index of the heart's functional capacity. A new method has been developed for the non-invasive estimation of exercise SV (SVex). It requires the determination of the slope for the oxygen uptake versus heart rate relationship in the steady state of graded exercise testing (GXT). The product of the slope and a constant (reciprocal of an assumed value of the arterial oxygen content) equals an estimated value for SVex. It was validated in a previous study using invasive measurements while subjects were performing steady-state GXT. However, currently the most commonly used GXT protocols are non-steady state, e.g. protocols with 1-min increment durations. We tested the hypothesis that SVex is the same for steady-state and non-steady-state GXT. A total of 30 subjects (15 males and 15 females) served as subjects for the study. Each subject performed two GXTs on different days with different increment durations - 1 and 4 min. Ventilation and gas exchange were measured with the Vacumed metabolic cart. For the male subjects, the mean (SD) SVex values for the 1- and 4-min GXTs were 155.4 (39.5) and 134.6 (27.5) ml, respectively. The corresponding values for the female subjects were 151.6 (37.6) and 134.3 (36.4) ml. Paired t-test analysis demonstrated that for both genders the mean SVex for the 1-min GXT was significantly larger than the 4-min GXT mean value (P<0.05). Hence, the commonly used 1-min GXT does not yield the same values for SVex as the steady-state GXT.     

Short- and long-term prognostic value of graded exercise testing soon after myocardial infarction

We attempted to determine whether graded exercise testing (GXT) soon after a myocardial infarction (MI) using an unlimited metabolic equivalent (MET) level and target heart rate (HR) of 90% of the age-predicted maximal HR is a safe procedure and yields prognostic results different from tests that use lower level end points. We administered GXT to a random sample of 85 patients at a mean of 14.8 days post-MI. End points that included ST-segment depression (STD), angina pectoris (AP), ventricular ectopic activity, and achieved MET level during testing were evaluated as predictors of cardiac events that include death, recurrent nonfatal MI, and coronary artery bypass graft surgery. We conducted short-term follow-up monitoring for one year after the initial MI and long-term follow-up monitoring for a mean of 864.7 days. No serious complications occurred during testing. Angina pectoris, STD accompanied by AP, and achieved MET level were predictive (p less than .05) of future fatal and nonfatal cardiac events during the first year of follow-up monitoring. Fifty-nine percent of the patients with AP suffered a subsequent cardiac event within one year, whereas only 17% of those without AP experienced another cardiac event. Sixty-seven percent of the patients with both STD and AP had a subsequent cardiac event within one year, but only 22% of those without AP and STD had a subsequent cardiac event. For the long-term follow-up monitoring, the presence of AP and a low achieved MET level during testing were associated with subsequent cardiac events.(ABSTRACT TRUNCATED AT 250 WORDS)     

Reliability of graded exercise testing after traumatic brain injury: submaximal and peak responses

OBJECTIVE: To assess the reliability of the submaximal and peak responses to a treadmill graded exercise test in individuals recovering from traumatic brain injury. DESIGN: A total of 15 individuals (11 men, 4 women; 28.5 +/- 9.2 yrs) with moderate to severe traumatic brain injury admitted into a postacute residential treatment center 10 +/- 7 mos after injury performed two treadmill graded exercise tests separated by 4-8 days. Heart rate, oxygen consumption (in milliliters per minute per kilogram), minute ventilation (in liters per minute), and respiratory exchange ratio (carbon dioxide output/oxygen consumption) were continuously monitored at 1-min intervals. Submaximal and peak values were analyzed for absolute level of agreement using the intraclass correlation coefficient. RESULTS: The submaximal intraclass correlation coefficient values for all variables between minutes 3 and 7 ranged from 0.80 to 0.93. Submaximal intraclass correlation coefficients before and in the subsequent minutes were less than optimal for heart rate and minute ventilation. Lower intensity workloads elicited slightly better agreement than higher intensity workloads. The peak response intraclass correlation coefficients ranged from 0.77 (heart rate) to 0.92 (oxygen consumption). CONCLUSION: Despite the presence of other co-morbidities, subjects recovering from traumatic brain injury provided consistent individual responses, allowing for reliable assessments of cardiorespiratory conditioning programs. Assessments of ambulatory efficiency, endurance, and aerobic fitness adaptations as a result of treatment for persons with traumatic brain injury should include analyses of submaximal responses to graded exercise.     

Prognostic predictors for survival in patients with COPD using cardiopulmonary exercise testing

We studied the relationship between physiologic parameters in cardiopulmonary exercise testing (CPET) and prognosis in terms of survival time in patients with chronic obstructive pulmonary disease (COPD) in order to accurately assess the severity of the disease. From a group of 195 patients with COPD who had consecutively undergone CPET between July 1989 and October 1997, we enrolled 120 subjects (mean age 67.6 years, 104 males) with exertional dyspnoea into a cohort protocol. Of these subjects, 34 (28.3%) died during the 3-5-year follow-up period after CPET. By univariate analysis, the following factors were significantly associated with survival time: age, body mass index, %FVC, %FEV1, FEV1%, PaCO2 at rest, severity of exercise-induced hypoxemia evaluated by DeltaPaO2/DeltaVO2 (PaO2-slope), oxygen uptake, ventilation, tidal volume, PaCO2 and oxygen pulse at maximum exercise, as well as prescribing long-term oxygen therapy. By multivariate analysis, age and the PaO2-slope showed significance as independent prognostic factors, and the PaO2-slope was most closely associated with the survival time. These results reveal that CPET is a useful technique to accurately assess the relationship between the functional impairments and the prognosis of patients with COPD.     

Effectiveness of a behaviour graded activity program versus conventional exercise for chronic neck pain patients

Chronic neck pain is a common complaint in the Netherlands with a point prevalence of 14.3%. Patients with chronic neck pain are often referred to physiotherapy and, nowadays, are mostly treated with exercise therapy. It is, however, unclear which type of exercise therapy is to be preferred. Therefore, this study evaluates the effectiveness of behaviour graded activity (BGA) compared with conventional exercise (CE) for patients with chronic neck pain. Eligible patients with non‐specific chronic neck were randomly allocated to either BGA or CE. Primary treatment outcome is the patient's global perceived effect concerning recovery from complaint and daily functioning. Outcome assessment was performed at baseline, and at 4, 9, 26, and 52 weeks after randomization. Effectiveness was examined with general estimating equations analyses. Baseline demographics and patient characteristics were well balanced between the two groups. Mean age was 45.7 (SD 12.4) years and the median duration of complaints was 60 months. The mean number of treatments was 6.6 (SD 3.0) in BGA and 11.2 (SD 4.1) in CE. No significant differences between treatments were found in their effectiveness of managing patients with chronic neck pain. In both BGA and CE some patients reported recovery from complaints and daily function but the proportion of recovered patients did not exceed 50% during the 12‐month follow‐up period. Both groups showed clinically relevant improvements in physical secondary outcomes. International Standard Randomised Controlled Trial Number: ISRCTN88733332.     

Lower extremity amputees with peripheral vascular disease: graded exercise testing and results of prosthetic training

Thirty-nine subjects, mean age 72 (range 52 to 89), with a leg amputation because of peripheral vascular disease performed graded exercise testing at the start of their prosthetic training program. Their walking performance at the end of the program was assessed and compared with the test findings. They had a history and rest electrocardiogram (ECG) examination which revealed cardiac problems in 75% of the patients. The exercise test was performed on a specially designed arm ergometer permitting coordinated exercise of arm and trunk muscles. Cardiac condition was judged by the achieved peak heart rate (mean 125 +/- 3.8 beats per minute) and observed ECG abnormalities. In only three patients exercise-induced ECG abnormalities were found at peak workload. The mean peak workload was 52 +/- 1.9W. It was concluded from these results that the average physical and cardiac condition is poor in vascular leg amputees. In 34 patients (87%) the prosthetic training was successful. Fourteen patients needed a walking frame and twenty could walk without a walking frame. The probability of achieving walking without a walking frame was 70% in patients with peak workload above 45W and 30% in those with peak workload lower than 45W.     

心肌做功联合心肺运动试验对肥厚型心肌病患者的预后评估

目的 利用心肌做功联合心肺运动试验(CPET)对HCM患者的预后进行评估,并探究心肌做功参数和CPET参数与左室壁厚度的相关性。方法 选取自2022年1月至2023年3月在福建省龙岩市第一医院确诊的非梗阻性HCM患者55例（男40例,女15例,平均年龄22-66岁）,同时选取健康志愿者55例作为对照组。收集常规超声心动图数据并进行两组间比较。HCM患者及对照组进行心肺运动试验,比较两组心肺运动试验参数及心肌做功参数的差异,并对两组在心肺运动试验前后心肌做功的参数变化进行比较。结果 HCM组与对照组相比最大室壁厚度（MWT）、左房舒张末内径（LAD）、E/e’均明显增加,差异有统计学意义（P<0.05）。HCM 组与对照组相比心肺运动试验前左室心肌做功参数整体纵向应变（GLS）、及心肌做功指数（GWI）和有用功（GCW）均明显降低,纵向应变达峰时间离散度 （PSD）明显升高,差异具有统计学意义（P<0.05）,而无用功（GWW）无明显统计学意义。HCM组与对照组相比心肺运动试验参数峰值摄氧量（Peak VO2）、无氧阈（AT）、氧脉搏（VO2/HR）和代谢当量（METs）均明显降低,差异有统计学意义（P<0.05）;VE/V?CO2斜率无明显升高。HCM组心肺运动试验前后GCW无明显升高,PSD明显升高;对照组心肺运动试验前后GCW明显升高相比,PSD无明显改变。左室最大室壁厚度与PSD呈正相关（r=0.88）,与GCW呈负相关（r=-0.84）,与VO2呈无明显负相关性（r=-0.48）。结论 心肌做功联合 CPET能够对HCM患者的预后进行有效评估,心肌有效做功参数与左室壁厚度呈负相关, CPET参数与左室壁厚度无明显相关性。     

Referral for coronary angiography after exercise testing: traditional decision-making versus decision analysis

To audit the referral decisions made by a single cardiologistfor coronary angiography after exercise testing, we retrospectivelyreviewed the charts of 303 consecutive patients in a communityhospital. The outcomes of these decisions, in terms of angiogramsperformed and quality-adjusted life expectancy gains as predictedby a decision analysis model, were compared with the theoreticaldecisions that would have been made using the model. The 97patients sent for angiography exercised for a shorter time (5.6± 3.1 vs. 6.9 ± 3.2 min, p<0.001) had moreST deviation (2.7 ± 1.4 vs. 1.7 ± 1.0 mm, p<0.001),more angina (53.6 vs. 36.9% of patients, p<0.01) and weremore likely to have had a previous myocardial infarction (59.8vs. 33.5% of patients, p<0.001) than the 206 not referred.However, of those not referred, 137 were each predicted to gainup to 5.7 quality-adjusted life years (QALYs) from bypass surgery.The overall predicted gain from the cardiologist's decisionswas only 0.1±2.5 QALYs/patient. Had the decisions beenmade using the model, the mean gain would have been 1.9±1.3QALYs/patient, and an extra 128 patients would have been sentfor angiography. Decision analysis makes consistent decisionswith defined risks and benefits. Such decisions can be reproduced,reviewed and analysed, whereas traditional decision-making mayinconsistently reflect the clinician's beliefs and values.     

Innovative endpoint determination system for antifungal susceptibility testing of yeasts.

Fungal infections and antifungal resistance are increasingly recognized. Antifungal susceptibility testing remains unstandardized, and a particularly important problem is endpoint determination. In this paper we propose the yeast metabolic reduction of the tetrazolium salt 2,3-bis(2- methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)carbonyl]-2H-tetraz olium hydroxide (XTT) as a colorimetric endpoint which is quantitative and objective. Amphotericin B, fluorocytosine, and fluconazole dose-response curves were obtained, and a metabolic MIC could be determined by using precise criteria.     

Comparative yield of HCV RNA testing in blood donors screened by 2.0 versus 3.0 antibody assays

BACKGROUND: Two HCV antibody tests (EIA 2.0 [EIA2], Abbott; and the Version 3.0 ELISA [EIA3], Ortho) are currently licensed for screening of US blood donors. Testing of donors for HCV RNA allows comparison of the sensitivities of the two antibody-screening assays. STUDY DESIGN AND METHODS: All allogeneic blood donations at 13 US test sites were screened for HCV RNA by testing plasma minipools using an investigational assay (COBAS AmpliScreen HCV test, v2.0, Roche Molecular Systems). Some sites screened for HCV antibody by EIA2 and some used EIA3. The frequency of RNA-positive and antibody-negative (RNA-pos and Ab-neg) donations among donors screened by each antibody assay was compared. Antibody appearance was assessed in a donor follow-up study. RESULTS: A total of 5.51 x 10(6) donations were screened for HCV RNA. Of these, 2.27 million were screened for antibody by EIA2, and 3.24 million by EIA3. Twenty-three donations were HCV RNA-pos and Ab-neg. The frequency of RNA-pos and Ab-neg donations was higher among donations screened by EIA2 (1 in 134,000), compared to those screened by EIA3 (1 in 540,000) (p = 0.001). Of the 17 RNA-pos and Ab-neg donations identified by test sites that used EIA2, 14 were retested by EIA3 and 10 (71%) were reactive. Most RNA-pos and Ab-neg donors appear to be in the process of seroconversion. Donors that were initially EIA2-negative and EIA3-reactive showed a more prolonged pattern of seroconversion compared to those that were initially nonreactive by both antibody assays. Four donors were EIA2-negative, EIA3-reactive, and RIBA-indeterminate (c33c) for at least 90 days, 1 for more than 317 days. CONCLUSION: EIA3 would have detected the majority of RNA-positive donations missed by EIA2. Some RNA-positive donors are EIA2-negative and EIA3-reactive for a prolonged period of time.     

分级等长收缩运动对正常人和心肌梗塞患者二尖瓣血流的影响——脉冲超声多普勒的研究

采用二维超声和脉冲超声多普勒对13例心肌梗塞患者和10名正常人进行研究,发现在近极量持续性肱二头肌和股四头肌等长收缩运动时患者最大二尖瓣舒张早期充盈速率(PE)下降,舒张晚期充盈速率(PA)升高,E/A比率下降,舒张时间缩短,与正常人的反应相似,两组诸指标的绝对差异在运动时缩小。提示这一现象可能为一种生理性反应,而不能简单地用心肌缺血来解释。     

Understanding the basics of cardiopulmonary exercise testing

Cardiopulmonary exercise testing adds important additional information to that provided by the standard exercise test. In particular, cardiopulmonary exercise testing provides precise determination of aerobic capacity, the causes of dyspnea with exertion, and prognosis in patients with systolic heart failure. This review provides basic, practical information about cardiopulmonary exercise testing for the clinician.     

Chronic Fatigue Syndrome: A description of graded exercise treatment

Patients with chronic fatigue syndrome complain of exercise intolerance and weakness, which may be partially related to lack of physical conditioning. Recent studies suggest that graded exercise therapy is a helpful treatment for the majority of patients. This article describes how to apply the treatment, adapted for clinical use. This incorporates recommendations and protocols for assessment of patients at baseline and throughout treatment, and details on monitoring of progression, through a low intensity graded exercise programme.     

Antimicrobial susceptibility testing of Bilophila wadsworthia by using triphenyltetrazolium chloride to facilitate endpoint determination.

Initial susceptibility studies of Bilophila wadsworthia indicated significant resistance to several beta-lactam antibiotics, including imipenem and cefoxitin. NO beta-lactamase production was detected. However, some B. wadsworthia strains may grow as a heavy "haze" at up to the highest concentration of an antibiotic on standard antimicrobial agent-containing plates, and it is often difficult to determine the point at which conventional growth stops and haze growth begins. We investigated the nature of the haze growth of B. wadsworthia by using triphenyltetrazolium chloride (TTC) as an indicator of viability during antimicrobial susceptibility testing, by determining viability counts on antimicrobial agent-containing plates at various times, and by microscopically inspecting stained preparations of the growth on the control plate and the haze area. TTC MICs were determined by applying a TTC solution over the growth on plates inside the anaerobic chamber or within 5 min after exposure to air (aerobic TTC MICs). The haze growth reduced TTC in the chamber but not under aerobic conditions, whereas TTC was reduced by the conventional growth in both atmospheres. The aerobic TTC MICs correlated with the viability counts. Separated proteins resolved by polyacrylamide gel electrophoresis and isoelectric focusing showed TTC-reactive bands only when stained under anaerobic conditions, further demonstrating the sensitivity of TTC reduction to aerobic conditions. Microscopic examination of the haze growth indicated spheroplast formation. A new antibiogram for B. wadsworthia has been established by use of aerobic TTC endpoints; we believe that the lower MICs obtained with the TTC method are likely the ones that are clinically relevant and should be used in tests of B. wadsworthia. Also, we found that when the organisms were grown on pyruvate-containing medium, 87% of 56 strains tested were Beta-lactamase positive.     

Clinical application of exercise testing in heart failure

Patients with heart failure frequently complain of fatigue and/or dyspnea during daily life. These exertional symptoms can be evaluated by the cardiopulmonary exercise testing. Peak oxygen uptake, anaerobic threshold(AT), the ratio of the increase in minute ventilation to the increase in carbon dioxide output(VE-VCO2 slope), the slope of the increase in oxygen uptake relative to the increase in work rate (delta VO2/delta WR), and the time constant of oxygen uptake (tau on) are reported to be useful to assess the severity and prognosis of heart failure patient. The information obtained from cardiopulmonary exercise testing can be used to select therapeutic option to improve both functional capacity and prognosis, and to identify patients with the greatest need for cardiac transplantation.     

The effects of maximal treadmill graded exercise testing on haemorheological, haemodynamic and flow cytometry platelet markers in patients with systolic or diastolic heart failure

Background Acute exercise has been associated with activation of thrombosis, and this risk may be accentuated in patients with heart failure. Given the relation of platelets to atherothrombosis, we tested the hypothesis that acute exercise would adversely affect platelet indices and platelet activation markers in patients with systolic and diastolic heart failure. Materials and methods We studied 20 patients with systolic heart failure (17 men, 3 women; mean age 64 ± 10 years, all with ejection fraction (EF) ≤ 40%) and 20 patients with diastolic heart failure (14 men, 6 women; mean age 64 ± 8 years, mean EF = 66%) who were exercised to maximal intensity, who were compared to 13 healthy controls (6 men, 7 women; mean age 60 ± 4 years, mean EF = 73%). We measured platelet indices (platelet volume, mass and component) and platelet activation markers (platelet‐bound CD62P%G, CD63%G and CD40L%G using flow cytometry, as well as plasma sCD40L and soluble P‐selectin (sP‐sel) levels). Results Baseline Mean Platelet Volume (MPV), sP‐sel, CD40L%G and CD63%G levels were significantly higher in patients with systolic and diastolic heart failure, when compared with controls. The mean exercise duration and VO₂ peak in patients with systolic and diastolic heart failure were not significantly different, but lower than that seen in healthy controls. Following exercise, mean haematocrit, CD62P%G, and CD63%G significantly increased in all three subject groups (all P < 0·05). The proportional change in CD62P%G and CD63%G were not significantly different between healthy controls and heart failure patients (P > 0·05). Conclusion Acute maximal graded exercise increases platelet activation markers, with no disproportionate differences between heart failure patients and healthy controls, despite the former group having a lower exercise tolerance and VO₂ peak.