BACKGROUND & AIMS: BACKGROUND:The complement system is an important mediator of inflammation, which plays a pivotal role in atherosclerosis and acute myocardial infarction (AMI). Animal studies suggest that activation of the complement cascade resulting in the formation of soluble membrane attack complex (sMAC), contributes to both atherosclerosis and plaque rupture and may be the direct cause of tissue damage related to ischemia/reperfusion injury. However clinical data of sMAC during an AMI is sparse. Accordingly the aim was to investigate the prognostic role of sMAC in patients with ST-segment elevation myocardial infarction (STEMI). METHODS:We included 725 STEMI-patients admitted to a single, high-volume invasive heart centre, treated with primary percutaneous coronary intervention (PCI), from September 2006 to December 2008. Blood samples were drawn immediately before PCI. Plasma sMAC was measured using an in-house immunoassay. Endpoints were all-cause mortality (n = 62) and the combined endpoint (n = 122) of major cardiovascular events (MACE) defined as cardiovascular mortality and admission due recurrent AMI or heart failure. Follow-up time was 12 months. RESULTS:During 12 months of follow-up 62 patients died from all causes and 122 patients reached the combined end-point of MACE. Patients with high sMAC (>75th percentile) had increased risk of both all-cause mortality and MACE. Even after adjustment for confounding risk factors by Cox-regression analyses, high levels of sMAC remained an independent predictor of all-cause mortality (hazard ratio 1.81 [95% CI 1.06-3.06; P = .029]) and MACE (hazard ratio 1.70 [95% CI 1.16-2.48; P = .006]). CONCLUSIONS:High plasma sMAC independently predicts all-cause mortality and MACE in STEMI-patients treated with PCI.

背景与目标：

BACKGROUND & AIMS: BACKGROUND:Circulating microRNAs (miRs) have emerged as potential diagnostic markers in patients with myocardial infarction. Previous studies, however, were based on limited patient numbers and could not assess the relation of miRs to myocardial damage. Moreover, the prognostic value of miRs in ST-elevation myocardial infarction (STEMI) is unknown. The aims of this study were (1) to assess the relation between miR-133a and myocardial damage assessed by cardiovascular magnetic resonance (CMR) imaging and (2) to evaluate the prognostic value of miR-133a in reperfused STEMI. METHODS:MicroRNA-133a concentrations were determined in 216 consecutive patients with STEMI undergoing primary angioplasty less than 12 hours after symptom onset. Patients were categorized into 2 groups defined by the median miR-133a value on admission. Cardiovascular magnetic resonance was performed for assessment of infarct size, myocardial salvage, and microvascular obstruction. The primary clinical end point was the occurrence of major adverse cardiovascular events defined as a composite of death, reinfarction, and new congestive heart failure within 6 months after infarction. RESULTS:All prognostic relevant CMR markers (infarct size, microvascular obstruction, myocardial salvage index) showed significant correlations with circulating miR-133a concentrations (P < .001 for all).The strongest predictors of miR-133a concentrations were the time from symptom onset to reperfusion and the amount of the salvaged area at risk. Major adverse cardiovascular events occurred significantly more often in the miR-133a ≥ median group (9% vs 20%, P = .025). However, miR-133a concentrations were unable to independently predict clinical events. CONCLUSIONS:Elevated levels of circulating miR-133a in patients with STEMI are associated with decreased myocardial salvage, larger infarcts, and more pronounced reperfusion injury. Consequently, miR-133a concentrations can provide prognostic information but do not add independent prognostic information to traditional and CMR markers of clinical prognosis in a high-risk STEMI population.

背景与目标：

BACKGROUND & AIMS: :Myocardial extracellular volume fraction (ECV) reflecting diffuse myocardial fibrosis can be measured with T1 mapping cardiovascular magnetic resonance (CMR) before and after the application of a gadolinium-based extracellular contrast agent. The equilibrium between blood and myocardium contrast concentration required for ECV measurements can be obtained with a primed contrast infusion (equilibrium contrast-CMR). We hypothesized that equilibrium can also be achieved with a single contrast bolus to accurately measure diffuse myocardial fibrosis in patients with congenital heart disease (CHD). Healthy controls (n = 17; median age 24.0 years) and patients with CHD (n = 19; 25.0 years) were prospectively enrolled. Using modified Look-Locker inversion recovery T1 mapping before, 15 min after bolus injection, and during constant infusion of gadolinium-DOTA, T1 values were obtained for blood pool and myocardium of the left ventricle (LV), the interventricular septum (IVS), and the right ventricle (RV) in a single midventricular plane in short axis or in transverse orientation. ECV of LV, IVS and RV by bolus-only and bolus-infusion correlated significantly in CHD patients (r = 0.94, 0.95, and 0.74; p < 0.01, respectively) and healthy controls (r = 0.96, 0.89, and 0.64; p < 0.05, respectively). Bland-Altman plots revealed no significant bias between the techniques for any of the analyzed regions. ECV of LV and RV myocardium measured by bolus-only T1 mapping agrees well with bolus-infusion measurements in patients with CHD. The use of a bolus-only approach facilitates the integration of ECV measurements into existing CMR imaging protocols, allowing for assessment of diffuse myocardial fibrosis in CHD in clinical routine.

背景与目标： : 反映弥漫性心肌纤维化的心肌细胞外体积分数 (ECV) 可以在施用基于g的细胞外造影剂之前和之后用T1映射心血管磁共振 (CMR) 测量。ECV测量所需的血液和心肌对比浓度之间的平衡可以通过灌注对比输注 (平衡对比-CMR) 获得。我们假设，通过单次对比推注也可以实现平衡，以准确测量先天性心脏病 (CHD) 患者的弥漫性心肌纤维化。前瞻性地纳入健康对照 (n   =   17; 中位年龄24.0岁) 和CHD患者 (n   =   19; 25.0岁)。在推注前，推注后15分钟以及在不断输注g-DOTA期间，使用改良的Look-Locker反转恢复T1映射，获得左心室 (LV)，室间隔 (IVS) 的血池和心肌的T1值，和右心室 (RV) 在单个心室中平面中的短轴或横向方向。在CHD患者 (分别为r   =   0.94、0.95和0.74; P  <  0.01) 和健康对照组 (分别为r   =   0.96、0.89和0.64; P  <  0.05) 中，仅推注和推注LV、IVS和RV的ECV显著相关。Bland-Altman图显示，任何分析区域的技术之间都没有明显的偏差。通过仅推注T1映射测量的LV和RV心肌的ECV与冠心病患者的推注测量非常吻合。仅推注方法的使用有助于将ECV测量结果集成到现有的CMR成像协议中，从而可以在临床常规中评估CHD中的弥漫性心肌纤维化。

BACKGROUND & AIMS: BACKGROUND AND OBJECTIVE:Shared decision making and advance planning in end-of-life decisions have become increasingly important aspects of the management of seriously ill patients. Here, we describe the use and timing of do-not-resuscitate (DNR) orders in patients hospitalized with acute myocardial infarction (AMI). STUDY DESIGN AND SETTING:The nonconcurrent prospective study population consisted of 4182 patients hospitalized with AMI in central Massachusetts in four annual periods between 2001 and 2007. RESULTS:One-quarter (25%) of patients had a DNR order written either prior to or during hospitalization. The frequency of DNR orders remained constant (24% in 2001; 26% in 2007). Among patients with DNR orders, there was a significant increase in orders written prior to hospitalization (2001: 9%; 2007: 55%). Older patients and those with a medical history of heart failure or myocardial infarction were more likely to have prior DNR orders than respective comparison groups. Patients with prior DNR orders were less likely to die 1 month after hospitalization than patients whose DNRs were written during hospitalization. CONCLUSION:Although the use of DNR orders in patients hospitalized with AMI was stable during the period under study, in more recent years, patients are increasingly being hospitalized with DNR orders already in place.

背景与目标：

BACKGROUND & AIMS: :Purpose. To evaluate whether 3T clinical MRI with a small-animal coil and gradient-echo (GE) sequence could be used to characterize long-term left ventricular remodelling (LVR) following nonreperfused myocardial infarction (MI) using semi-automatic segmentation software (SASS) in a rat model. Materials and Methods. 5 healthy rats were used to validate left ventricular mass (LVM) measured by MRI with postmortem values. 5 sham and 7 infarcted rats were scanned at 2 and 4 weeks after surgery to allow for functional and structural analysis of the heart. Measurements included ejection fraction (EF), end-diastolic volume (EDV), end-systolic volume (ESV), and LVM. Changes in different regions of the heart were quantified using wall thickness analyses. Results. LVM validation in healthy rats demonstrated high correlation between MR and postmortem values. Functional assessment at 4 weeks after MI revealed considerable reduction in EF, increases in ESV, EDV, and LVM, and contractile dysfunction in infarcted and noninfarcted regions. Conclusion. Clinical 3T MRI with a small animal coil and GE sequence generated images in a rat heart with adequate signal-to-noise ratio (SNR) for successful semiautomatic segmentation to accurately and rapidly evaluate long-term LVR after MI.

背景与目标： : 目的。评估是否可以使用半自动分割软件 (SASS) 在大鼠模型中使用带有小动物线圈和梯度回波 (GE) 序列的3t临床MRI来表征非再灌注心肌梗死 (MI) 后的长期左心室重塑 (LVR)。材料和方法。5只健康大鼠用于验证MRI测量的左心室质量 (LVM) 和死后值。在手术后2周和4周对5只假手术大鼠和7只梗死大鼠进行扫描，以进行心脏的功能和结构分析。测量包括射血分数 (EF)，舒张末期容积 (EDV)，收缩末期容积 (ESV) 和LVM。使用壁厚分析来量化心脏不同区域的变化。结果。健康大鼠的LVM验证表明MR与死后值之间存在高度相关性。MI后4周的功能评估显示EF显着降低，ESV，EDV和LVM增加以及梗塞和非梗塞区域的收缩功能障碍。结论。具有小动物线圈和GE序列的临床3T MRI在大鼠心脏中生成的图像具有足够的信噪比 (SNR)，可成功进行半自动分割，以准确，快速地评估MI后的长期LVR。

BACKGROUND & AIMS: BACKGROUND:Reductions in admissions for myocardial infarction (MI) have been reported in locales where smoke-free workplace laws have been implemented, but no study has assessed sudden cardiac death in that setting. In 2002, a smoke-free restaurant ordinance was implemented in Olmsted County, Minnesota, and in 2007, all workplaces, including bars, became smoke free. METHODS:To evaluate the population impact of smoke-free laws, we measured, through the Rochester Epidemiology Project, the incidence of MI and sudden cardiac death in Olmsted County during the 18-month period before and after implementation of each smoke-free ordinance. All MIs were continuously abstracted and validated, using rigorous standardized criteria relying on biomarkers, cardiac pain, and Minnesota coding of the electrocardiogram. Sudden cardiac death was defined as out-of-hospital deaths associated with coronary disease. RESULTS:Comparing the 18 months before implementation of the smoke-free restaurant ordinance with the 18 months after implementation of the smoke-free workplace law, the incidence of MI declined by 33% (P < .001), from 150.8 to 100.7 per 100,000 population, and the incidence of sudden cardiac death declined by 17% (P = .13), from 109.1 to 92.0 per 100,000 population. During the same period, the prevalence of smoking declined and that of hypertension, diabetes mellitus, hypercholesterolemia, and obesity either remained constant or increased. CONCLUSIONS:A substantial decline in the incidence of MI was observed after smoke-free laws were implemented, the magnitude of which is not explained by community cointerventions or changes in cardiovascular risk factors with the exception of smoking prevalence. As trends in other risk factors do not appear explanatory, smoke-free workplace laws seem to be ecologically related to these favorable trends. Secondhand smoke exposure should be considered a modifiable risk factor for MI. All people should avoid secondhand smoke to the extent possible, and people with coronary heart disease should have no exposure to secondhand smoke.

背景与目标：

BACKGROUND & AIMS: AIMS:We sought to evaluate bleeding complications and periprocedural outcomes of the radial approach (RA) as compared to the femoral approach (FA) during percutaneous coronary intervention (PCI) in "real-world" patients with ST-segment elevation myocardial infarction (STEMI). METHODS AND RESULTS:The study group consisted of 22,812 consecutive patients with STEMI treated with PCI and stent implantation between January 2014 and June 2015 in 151 tertiary invasive cardiology centres in Poland (the ORPKI Polish National Registry). Patients treated using the RA and FA were compared using a propensity score analysis to avoid possible selection bias. The analysis was carried out in an "as-treated" manner. The FA was used in 9,334 (40.9%) and the RA in 13,478 (59.1%) patients. After propensity score matching, a higher total amount of contrast (191.8±8.0 vs. 174.8±68.8 ml; p=0.001) and lower radiation doses (1,279.5±1,346.3 vs. 1,182.6±887 mGy; p=0.02) were reported in FA. More access-site-related bleeding complications after both angiography (0.17% vs. 0.02%; p=0.004) and PCI (0.23% vs. 0.09%; p=0.049) were reported in the FA group. Periprocedural death (1.94% vs. 0.93%; p=0.001) was more common after PCI performed with the FA. CONCLUSIONS:The radial approach was associated with a lower incidence of periprocedural death in STEMI patients as well as a significant reduction of bleeding complications at the access site.

背景与目标：

BACKGROUND & AIMS: OBJECTIVE:Statins reduce inflammation and risk of myocardial infarction (MI). Because the myeloid IgA Fc receptor encoded by FCAR mediates inflammation, we hypothesized that the FCAR Asp92Asn polymorphism is associated with risk of MI and that this risk would be modified by pravastatin. METHODS AND RESULTS:In the placebo arm of the Cholesterol and Recurrent Events (CARE) study, male carriers of the 92Asn allele had an adjusted hazard ratio for incident MI of 1.68 (95% CI 1.10 to 2.57); relative risk reduction by pravastatin was 69% in carriers and 12% in noncarriers (P(interaction)=0.007). In the placebo arm of the all-male West of Scotland Coronary Prevention Study (WOSCOPS), carriers had an adjusted odds ratio for incident coronary heart disease (CHD) of 1.46 (90% CI 1.05 to 2.03); for pravastatin compared with placebo treatment, the adjusted odds ratios were 0.55 (95% CI 0.32 to 0.93) in carriers and 0.65 (95% CI 0.51 to 0.83) in noncarriers (P(interaction)=0.55). CONCLUSIONS:Carriers of 92Asn had increased risk of MI in CARE and increased odds of CHD in WOSCOPS. Pravastatin significantly reduced risk in carriers in both CARE and WOSCOPS. A genotype by treatment interaction was observed in CARE but not in WOSCOPS.

背景与目标：

BACKGROUND & AIMS: PURPOSE:The purpose of this study was to assess demographic characteristics of women prescribed beta-blocker (beta-blocker) medication and compare to those not using beta-blocker medication, and to determine if there are differences in depression and fatigue among women who used beta-blockers compared to nonusers 6-12 months after myocardial infarction (MI). DATA SOURCES:This was a descriptive cross-sectional study of 84 women (61 using beta-blockers and 23 not using beta-blockers) aged 65 and older who were 6-12 months post-MI. Women had their height and weight measured and completed a Demographic Health Form, the Geriatric Depression Scale, and the Revised Piper Fatigue Scale (RPFS). CONCLUSIONS:While most of the women were taking beta-blockers after MI (74%), significantly fewer Black women were taking beta-blockers (chi(2) = 5.086, p = 0.032). Most of the beta-blocker users were overweight or obese. There were no significant differences in age, t(82) = 0.7, p = 0.486; body mass index, t(82) = 0.76, p = 0.445; income, chi(2)(df = 2) = 3.219, p = 0.075; mean depression, t(82) = 1.648, p = 0.103; or fatigue scores, t(82) = 0.993, p = 0.324, between beta-blocker users and nonusers. More of those not taking beta-blockers reported fatigue with significantly higher fatigue in the affective meaning dimension of the RPFS, t(82) = 2.272, p = 0.03. IMPLICATIONS FOR PRACTICE:beta-Blocker medication continues to be underutilized in older women. Because no difference was noted in fatigue and depression in the two groups, these may mean that these side effects are not barriers in prescribing this medication post-MI. Nurse practitioners are in pivotal positions to monitor the ongoing physiological and psychological sequelae post-MI and implement interventions to improve their outcomes.

背景与目标：

BACKGROUND & AIMS: :This study, conducted over two time periods, aimed to evaluate the effectiveness of the diffusion of data, implementation of correctives measures and updated protocols in reducing time to reperfusion in acute myocardial infarction (AMI) management in the out-of-hospital setting. Mean (SD) time to hospital admission and to arterial puncture improved (58 (13) vs 67 (18) min, p = 0.03; and 82 (16) vs 95 (29) min, p = 0.02). The study, performed according to quality control programme methodology, showed that the chronology of AMI management could be improved by appropriate interventions and monitoring of intervention times.

背景与目标： : 这项研究在两个时间段内进行，旨在评估数据扩散的有效性，纠正措施的实施以及更新的方案在减少医院外急性心肌梗塞 (AMI) 管理中的再灌注时间方面的有效性设置。平均 (SD) 入院和动脉穿刺时间改善 (58 (13) vs 67 (18) 分钟，p = 0.03; 和82 (16) vs 95 (29) 分钟，p = 0.02)。根据质量控制计划方法进行的研究表明，可以通过适当的干预和监测干预时间来改善AMI管理的时间顺序。

BACKGROUND & AIMS: The incidence of acute myocardial infarction (AMI) among urban blacks appears to be considerably less than that among whites. To evaluate this, all AMIs among Newark, NJ, residents in 1973 were evaluated, using the 1970 census for calculating age, race, and sex-specific rates. Death certificates of patients dead on arrival (DOA) from coronary heart disease (total 517) were also evaluated. Two hundred seventy-three AMIs were documented. Although crude rates per 100,000 population were higher for whites than for blacks, age-specific rates by decades from 20 to 80 revealed no differences. Coronary DOA rates were consistently higher among blacks than among whites, reaching approximately a 21 ratio in the older decades. The apparent rarity of AMI among Newark blacks is attributable to their relative youth compared to whites (77% under 40 vs 56%) and a higher out-of-hospital coronary death rate.

背景与目标： 城市黑人的急性心肌梗死 (AMI) 发生率似乎比白人低得多。为了评估这一点，使用1970年人口普查来计算年龄，种族和性别特定比率，对新泽西州纽瓦克市1973年的所有ami进行了评估。还评估了因冠心病 (总517) 而死亡的患者的死亡证明。记录了二百一十三名非盟特派团。尽管白人每100,000人口的粗比率高于黑人，但从20到80的数十年的特定年龄比率没有差异。黑人的冠状动脉DOA率始终高于白人，在过去的几十年中，这一比例约为21。纽瓦克黑人中AMI的明显稀有性归因于他们与白人相比相对年轻 (40岁以下的77% 比56% 岁) 和较高的院外冠状动脉死亡率。

BACKGROUND & AIMS: :To study the force-velocity characteristics of human knee-hip extension movement, a dynamometer, in which force was controlled by a servo system, was developed. Seated subjects pressed either bilaterally or unilaterally a force plate, a horizontal position of which was servo-controlled so as to equalize the measured force and a force command generated by a computer at a time resolution of 2 ms (force clamp). The force command was based on the relation between maximum isometric force and foot position within the range between 70% and 90% of "leg length" (LL: longitudinal distance between the sole of the foot and the hip joint), so that the same force relative to the maximum isometric force was consistently applied regardless of the foot position. By regulating the force according to this function, the force-velocity relation was determined. The force-velocity relation obtained was described by a linear function (n=17, r=-0.986 for 80% LL, r=-0.968 for 85% LL) within a range of force between 0.1 and 0.8F(0) (maximum isometric force). The maximum force extrapolated from the linear regression (F(max)) coincided with F(0) (n=17, F(0)/F(max)=1.00+/-0.09 for 80% LL and 1.00+/-0.20 for 85% LL). Also, the velocity at zero force (V(max)) was obtained from the extrapolation. When compared to the bilateral movements, unilateral movements gave rise to a smaller F(max) but the same V(max), suggesting that V(max) is independent of force and therefore represents the proper unloaded velocity. It is suggested that some neural mechanisms may be involved in the force-velocity relation of the knee-hip extension movement, and make it exhibit a linear appearance rather than a hyperbola.

背景与目标： : 为了研究人体膝关节-髋关节伸展运动的力-速度特性，开发了一种测力计，该测力计由伺服系统控制。就座的对象在两侧或一侧按压一个测力板，其水平位置受到伺服控制，以使测得的力和计算机以2 ms的时间分辨率 (力夹) 产生的力命令相等。力命令基于最大等距力和足部位置之间的关系，范围在 “腿长” 的70% 和90% 之间 (LL: 脚底和髋关节之间的纵向距离)，因此，无论脚的位置如何，都始终施加相对于最大等距力的相同力。通过根据此函数调节力，确定了力-速度关系。在0.1和0.8F(0) (最大等距力) 之间的力范围内，通过线性函数 (n = 17，对于80% LL，r =-0.986，对于85% LL，r =-0.968) 描述获得的力-速度关系。从线性回归外推的最大力 (F(max)) 与F(0) 一致 (对于80% LL，n = 17，F(0)/F(max)= 1.00 +/-0.09，对于85% LL，1.00 +/-0.20)。此外，通过外推获得了零力 (V(max)) 的速度。与双边运动相比，单边运动产生的F(max) 较小，但V(max) 相同，这表明V(max) 与力无关，因此代表适当的空载速度。建议某些神经机制可能参与膝髋伸展运动的力-速度关系，并使其表现出线性外观而不是双曲线。

BACKGROUND & AIMS: The purpose of this study was to determine if quantitative measurements of regional asynergy add independent prognostic information to global ejection fraction in patients with chronic coronary artery disease. Four hundred eighty-six patients with a history of Q-wave myocardial infarction who underwent gated-equilibrium radionuclide angiography at least 3 months after infarction were monitored for a median duration of 4.7 years. During follow-up there were 95 deaths. Four of five regional asynergy indexes analyzed were associated with overall mortality. The strength of the association between overall mortality and the index that proved to be optimal (univariate chi2 = 26.4, p < 0.001) was stronger than for global ejection fraction (univariate chi2 = 21.5, p < 0.001). For patients with global ejection fraction <40%, 4-year survival was 87% for those with a low asynergy index versus 65% for those with a high asynergy index (p = 0.016). In conclusion, indexes of regional asynergy add independent prognostic information to global left ventricular ejection fraction.

背景与目标： 这项研究的目的是确定区域不同步的定量测量是否为慢性冠心病患者的整体射血分数增加了独立的预后信息。对486例有Q波心肌梗死病史的患者进行了监测，这些患者在梗死后至少3个月接受了门控平衡放射性核素血管造影，中位持续时间为4.7年。在随访期间，有95人死亡。分析的五个区域异步指数中有四个与总体死亡率相关。总死亡率与被证明是最佳的指数 (单变量chi2 = 26.4，p <0.001) 之间的关联强度强于整体射血分数 (单变量chi2 = 21.5，p <0.001)。对于整体射血分数 <40% 的患者，非同步指数低的患者87% 4年生存率，而非同步指数高的患者65% (p = 0.016)。总之，区域非同步指数为整体左心室射血分数增加了独立的预后信息。

BACKGROUND & AIMS: :Purpose of this study was to assess the additional value of first pass myocardial perfusion imaging during peak dose of dobutamine stress Cardiac-MR (CMR). Dobutamine Stress CMR was performed in 115 patients with an inconclusive diagnosis of myocardial ischemia on a 1.5 T system (Magnetom Avanto, Siemens Medical Systems). Three short-axis cine and grid series were acquired during rest and at increasing doses of dobutamine (maximum 40 microg/kg/min). On peak dose dobutamine followed immediately by a first pass myocardial perfusion imaging sequence. Images were graded according to the sixteen-segment model, on a four point scale. Ninety-seven patients showed no New (Induced) Wall Motion Abnormalities (NWMA). Perfusion imaging showed absence of perfusion deficits in 67 of these patients (69%). Perfusion deficits attributable to known previous myocardial infarction were found in 30 patients (31%). Eighteen patients had NWMA, indicative for myocardial ischemia, of which 14 (78%) could be confirmed by a corresponding perfusion deficit. Four patients (22%) with NWMA did not have perfusion deficits. In these four patients NWMA were caused by a Left Bundle Branch Block (LBBB). They were free from cardiac events during the follow-up period (median 13.5 months; range 6-20). Addition of first-pass myocardial perfusion imaging during peak-dose dobutamine stress CMR can help to decide whether a NWMA is caused by myocardial ischemia or is due to an (inducible) LBBB, hereby preventing a false positive wall motion interpretation.

背景与目标： : 这项研究的目的是评估多巴酚丁胺应激心脏MR (CMR) 峰值剂量期间首过心肌灌注成像的附加价值。多巴酚丁胺应激CMR在1.5 T系统 (Magnetom Avanto，Siemens Medical Systems) 上对115例未明确诊断为心肌缺血的患者进行。在休息期间和增加多巴酚丁胺的剂量 (最大40微克/千克/分钟) 获得了三个短轴电影和网格系列。在峰值剂量多巴酚丁胺之后立即进行首过心肌灌注成像序列。根据十六段模型对图像进行了四分制的分级。97名患者未显示新的 (诱发的) 壁运动异常 (NWMA)。灌注成像显示这些患者中有67例 (69%) 不存在灌注缺陷。在30例患者 (31%) 中发现了可归因于已知先前心肌梗塞的灌注缺陷。18例患者患有NWMA，指示心肌缺血，其中14例 (78% 例) 可以通过相应的灌注不足来确认。四名NWMA患者 (22%) 没有灌注缺陷。在这四名患者中，NWMA是由左束支传导阻滞 (LBBB) 引起的。在随访期间 (中位13.5个月; 范围6-20)，他们没有心脏事件。在峰值剂量多巴酚丁胺应激CMR期间增加首过心肌灌注成像可以帮助确定NWMA是由心肌缺血引起还是由 (可诱导的) LBBB引起，从而防止假阳性壁运动解释。

BACKGROUND & AIMS: :Information about the future trajectory of a visual target is contained not only in the history of target motion but also in static visual cues, e.g., the street provides information about the car's future trajectory. For most natural moving targets, this information imposes strong constraints on the relation between velocity and acceleration which can be exploited by predictive smooth pursuit mechanisms. We questioned how cue-induced predictive changes in pursuit direction depend on target speed and how cue- and target-induced pursuit interact. Subjects pursued a target entering a +/-90 degrees curve and moving on either a homogeneous background or on a low contrast static band indicating the future trajectory. The cue induced a predictive change of pursuit direction, which occurred before curve onset of the target. The predictive velocity component orthogonal to the initial pursuit direction started later and became faster with increasing target velocity. The predictive eye acceleration increased quadratically with target velocity and was independent of the initial target direction. After curve onset, cue- and target-induced pursuit velocity components were not linearly superimposed. The quadratic increase of eye acceleration with target velocity is consistent with the natural velocity scaling implied by the two-thirds power law, which is a characteristic of biological controlled movements. Comparison with linear pursuit models reveals that the ratio between eye acceleration and actual or expected retinal slip cannot be considered a constant gain factor. To obey a natural velocity scaling, this acceleration gain must linearly increase with target or pursuit velocity. We suggest that gain control mechanisms, which affect target-induced changes of pursuit velocity, act similarly on predictive changes of pursuit induced by static visual cues.

背景与目标： : 有关视觉目标的未来轨迹的信息不仅包含在目标运动的历史中，而且还包含在静态视觉提示中，例如，街道提供有关汽车未来轨迹的信息。对于大多数自然运动目标，此信息对速度与加速度之间的关系施加了严格的约束，可以通过预测性平滑追踪机制加以利用。我们质疑线索诱导的追踪方向的预测变化如何取决于目标速度，以及线索和目标诱导的追踪如何相互作用。受试者追求目标，进入90度曲线并在均匀背景或低对比度静态带上移动，指示未来轨迹。提示引起了追踪方向的预测性变化，该变化发生在目标曲线开始之前。与初始追踪方向正交的预测速度分量稍后开始，并且随着目标速度的增加而变得更快。预测眼加速度随目标速度呈二次增加，并且与初始目标方向无关。曲线开始后，提示和目标诱导的追踪速度分量没有线性叠加。眼睛加速度随目标速度的二次增加与3分之2幂定律所隐含的自然速度标度一致，这是生物控制运动的特征。与线性追踪模型的比较表明，眼睛加速度与实际或预期的视网膜滑动之间的比率不能被视为恒定的增益因子。要服从自然速度缩放，此加速度增益必须随目标或追踪速度线性增加。我们建议影响目标引起的追踪速度变化的增益控制机制对静态视觉提示引起的追踪预测变化具有类似的作用。