先天性二尖瓣狭窄(瓣膜型)超声心动图

本文报告先天性二尖瓣狭窄5例的超声心动图特征。胸骨旁长轴切面:(1)二尖瓣轻度增厚,瓣叶冗长,瓣缘卷曲;(2)舒张期瓣尖开放呈圆拱顶状,且位置较低,接近乳头肌;(3)腱索显著缩短;(4)左室腔内肌性或纤维性条束错综交织,甚可影响二尖瓣的开放。二尖瓣短轴切面:(1)能探测到瓣叶的切面数增多;(2)二尖瓣口与乳头肌见于同一切面;(3)二尖瓣口面积缩小、偏心,偏向左室后壁;(4)二乳头肌发育不良,乳头肌间距离缩小。超声心动图可对先天性与风湿性二尖瓣狭窄作出鉴别:     

比较老年与中青年二尖瓣腱索断裂的超声心动图特征和规律性

目的：比较老年二尖瓣腱索断裂（RMCT）患者与中青年RMCT患者的临床表现以及超声心动图特点,为老年RMCT患者的诊断和治疗提供依据。方法：选择年龄〉60岁的老年RMCT患者53例定义为老年组,年龄〈60岁的中青年RMCT患者57例定义为中青年组,使用经胸超声心动图（TTE）和经食道超声心动图（TEE）测量各组的心腔尺寸,观察二尖瓣活动形态以及腱索断裂的部位和程度,记录瓣膜的返流情况。结果：老年组中风心病仅占5．66％,而中青年组风心病患者占50．88％,差异有统计学意义（X2=27．221,P=0．000）。老年组多合并有多种慢性疾病,其中合并高血压者占83．02％,合并冠心病者占60．38％,合并2型糖尿病者占37．74％,均高于中青年组,其中合并高血压的差异有统计学意义（X2=-31．459,P=0．000）。老年组中心功能Ⅳ级的比例远高于中青年组,差异有统计学意义（X2=10．489,P=0．001）。老年组全心扩大、肺动脉高压的例数显著高于中青年组,差异有统计学意义（全心扩大：XZ=11．376,P=0．001;肺动脉高压：X2=-20．362,P=0．000）。老年组中二尖瓣细小腱索断裂的例数多于中青年组,差异有统计学意义（x2=9．799,P=0．002）,粗大腱索断裂的例数少于中青年组,差异有统计学意义（x2=11．118,P=0．001）。结论：合并有高血压、冠心病以及糖尿病等基础疾病的老年RMCT患者,应定期进行超声心动图的检查,同时给予合理的治疗,以降低心衰的发病率。     

超声心动图测量二尖瓣环位移评价左室舒张功能

本文用超声心动图测量正常人和高血压病患者二尖瓣环位移,探讨该方法评价左室舒张功能价值。结果表明：高血压病组舒张期二尖瓣环位移最大幅度低于正常组,左房收缩引起二尖瓣环位移及Ａｔ／Ｔ比值均高于正常组,两组Ａｔ／Ｔ与Ａ／Ｅ之间均存在良好线性关系,Ａｔ／Ｔ诊断左室舒张功能异常的敏感性和特异性分别是９３％和８６％。     

基于改进C-V模型的超声心动图像轮廓的提取方法

目的:通过超声图像预处理和对图像分割方法的改进,完成超声心动图中心腔轮廓的提取。方法:首先,运用基于斑点指数的滤波方法对超声图像进行去噪。其次,对超声图像进行分段非线性灰度变换,提高图像对比度。最后,利用改进的基于C-V模型的水平集算法对超声图像进行分割,得到精确的初始轮廓。结果:1基于斑点指数的图像滤波方法可以在不丢失细节的情况下对超声图像进行噪声滤除。2分段非线性灰度变换可以有效提高超声图像的对比度。3改进的C-V模型可以成功的对含有斑点噪声的超声图像进行分割。结论:本文的超声图像预处理方法和分割算法可以有效提取心腔轮廓,降低斑点噪声对图像分割结果的影响。     

实时三维经胸超声心动图检测二尖瓣成形术前后左心房功能的变化及临床意义

目的:探讨实时三维经胸超声心动图检测左心房(LA)功能以评价二尖瓣成形术(MVR)疗效的价值。方法:选择87例二尖瓣关闭不全患者(病例组)分别在MVR术前及术后1 w、24 w采取实时三维经胸超声心动图检测LA的最大容积(maximum volume of LA,LAV_(max))、最小容积(the minimum volume of LA,LAV_(min))、收缩前容积(systolic volume,LAV_p)及射血分数(ejection fraction,LAEF)、被动射血分数(passive ejection fraction,LAPEF)及主动射血分数(active ejection fraction,LAAEF)等指标,并与同期80例健康志愿者作对照。结果:病例组术前LAV_(max)I、LAV_(min)I、LAV_pI、LAEF、LAPEF、LAAEF值与对照组比较差异有统计学意义(P0.05),术后1 w、24 w,LAV_(max)I、LAV_(min)I、LAV_pI、LAEF、LAPEF持续改善(P0.05),LAPEF无明显变化(P0.05)。术后24 w,LA严重扩张由术前58.6%降低到12.6%,67.8%发生LA重构。结论:实时三维经胸超声心动图显示MVR术后LA容积与功能好转,对评价MVR的疗效有一定价值。     

基于三维超声心动图对比分析扩张型心肌病与二尖瓣关闭不全左室构型和收缩功能的研究

摘要 目的：基于三维超声心动图对比分析扩张型心肌病（DCM）与二尖瓣关闭不全（MI）左室构型和收缩功能的研究。方法：收集我院2018年1月至2021年7月就诊患有左心室（LV）扩张的患者100例,其中DCM患者57例,MI患者43例。LV大小大致相仿,DCM组（43±5）mm/m²,MI组（42±5）mm/m²。另选取同时期50例健康受试者作为对照组。所有患者均进行常规超声心动图及三维超声心动图检查,测量指标主要包括左室大小（LVID）、左室后壁厚度（PWT）、左室舒张末期内径（LVEDD）、左室舒张末期室间间隔厚度（IVS）、左室舒张末期容积（LVEDV）、收缩末期容积（LVESV）、相对室壁厚度（RWT）、LV质量指数（LVMI）、三维左室射血分数（3D-LVEF）、三维舒张末期血流速度（3D-EDV）、二维或三维超声心动图球形指数（2D-SI/3D-SI）。结果：DCM组和MI组LVEDD均大于对照组,差异有统计学意义（P＜0.05）。DCM组比MI组患者心功能分级III/IV和心力衰竭的发生率更高,差异有统计学意义（P＜0.05）。DCM组和MI组患者的LVEDD、LVEDD指数、LVEDV、LVEDV指数、3D-EDV、3D-EDV指数均高于对照组,差异有统计学意义（P＜0.05）;但DCM组和MI组对比差异无统计学意义（P＞0.05）。DCM组和MI组患者的LV长度、LV长度指数、LVMI均高于对照组,差异有统计学意义（P＜0.05）;且MI组高于DCM组,差异有统计学意义（P＜0.05）。DCM组和MI组患者的LVESV、LVESV指数、2D-SI、3D-SI均高于对照组,差异有统计学意义（P＜0.05）;且DCM组高于MI组,差异有统计学意义（P＜0.05）。DCM组3D-LVEF、RWT均低于对照组和MI组,差异有统计学意义（P＜0.05）。ROC分析显示,3D-SI在评估左室扩大患者的左室重构方面优于其他变量,3D-SI的ROC曲线下面积为0.875,95%CI为0.816-0.920,3D-SI>0.62对于DCM和MI区分左室构型的特异性（81.66%）和敏感性（92.09%）较高。DCM和MI患者的3D-LVEF和3D-SI均呈线性负相关（r=-0.719,P=0.000;r=-0.682,P=0.000）。DCM和MI患者3D-SI检测心力衰竭的ROC曲线下面积均大于3D-LVEF的ROC曲线下面积,差异有统计学意义（P=0.000）。结论：与MI患者相比,尽管LV大小大致相仿,但DCM患者的左室几何形状更接近球形,且收缩功能更差。收缩功能与3D-SI显著相关,3D-SI较好地描述了左室重构,可能是LV扩张患者心力衰竭的较强指标。     

基于局部调整动态轮廓模型提取超声图像乳腺肿瘤边缘

提出一种基于局部调整动态轮廓模型提取超声图像乳腺肿瘤边缘的算法。该算法在Chan—Vese（CV）模型基础上,定义了一个局部调整项,采用基于水平集的动态轮廓模型提取超声图像乳腺肿瘤边缘。将该算法应用于89例临床超声图像乳腺肿瘤的边缘提取实验,结果表明：该算法比CV模型更适用于具有区域非同质性的超声图像的分割,可有效实现超声图像乳腺肿瘤边缘的提取。     

超声心动图对缺血性二尖瓣反流血流动力学的研究

目的:应用超声心动图研究缺血性二尖瓣反流(IMR)所致左室、二尖瓣环动力学变化。方法:超声心动图检测86例缺血性二尖瓣反流患者(前壁心肌梗死49例,下壁心肌梗死37例)和30例正常人的心脏,测量左室参数及二尖瓣环形态参数。结果:IMR组左室EDV、ESV增加,LVEF减低,但与对照组无显著差异;二尖瓣环面积及位移与对照组有显著差异;不同部位心肌梗死均发生明显左室重构;下壁梗死组PPM-AMP明显延长。结论:超声心动图作为心肌梗死患者的常规检查,可以针对不同患者进行不同的参数检查,这也为临床医生选择个性化治疗方案和疗效评价提供了依据。     

高血压病的复合超声心动图研究

现常用于检测高血压病的彩色、脉冲多普勒及二维、M型超声心动图几种方法,各有其优点与不足。本文利用其各自的优点,运用上述复合超声心动图法检测96例高血压病患者及86例正常人,进行了分析研究。认为,此法检诊高血压病是实用、可行的。     

高血压病的复俣超声心动图研究

现常用于检测高血压病的彩色、脉冲多普勒及二维、Ｍ型超声心动图几种方法,各有其优点与不足。本文利用其各自的优点,运用上述复合超声心动图法检测９６例高血压病患者及９６例正常人,进行了分析研究,认为,此法检诊高血压病是实用、可行的。     

二尖瓣成形术与二尖瓣生物瓣置换术治疗风湿性二尖瓣重度关闭不全的效果比较

目的:探讨二尖瓣成形术(Mitral valve plasty,MVP)与二尖瓣生物瓣置换术(Mitral valve replacement,MVR)治疗风湿性二尖瓣重度关闭的临床疗效和安全性。方法:选择我院2014年1月至2019年1月收治的因风湿性二尖瓣重度关闭而行二尖瓣成形术或二尖瓣生物瓣置换术的患者60例,其中二尖瓣成形术组(MVP组)27例,二尖瓣生物瓣置换术组(MVR组)33例。比较两组患者的围手术期各项指标,治疗前后的心功能指标(左心室射血分数,左心房内径、左心室收缩末期内径、左心室舒张末期内径)及二尖瓣反流情况以及术后并发症的发生情况。结果:(1)MVP组患者的手术时间、体外循环时间均明显长于MVR组(P0.05);而术中出血量、呼吸机使用时间、住院时间MVP组均显著低于MVR组(P0.05);(2)术后,MVP组的LVEF和LVEDD水平高于MVR组,而LAD和LVESD水平则低于MVR组(P 0.05);(3)出院前及末次随访时,MVP组二尖瓣反流发生率与MVR组相比差异均无统计学意义(P0.05)。(4)MVP组患者的术后并发症发生率低于MVR组(P 0.05)。结论:二尖瓣成形术治疗风湿性二尖瓣重度关闭的临床疗效和安全性优于二尖瓣生物瓣置换术,但术者需严格掌控MVP的手术适应症。     

Estimation of Residual Valve Gradient from Incomplete Data with Outliers

An important indicator for the long-term recovery after valve replacement surgery is postoperative valve gradient. This information is available only for patients received catheterization or echocardiogram postoperatively. It is plausible that sicker patients are more inclined to undergo these postoperative procedures and their valve gradients tend to be higher. Under this situation, ignoring the missing values and using sample mean based on the available information as an estimate of the whole study population leads to overestimation. Regression estimator is a reasonable choice to eliminate this bias if independent (explanatory) variables closely associated with both residual valve gradient and non-response mechanism can be identified. Using a series of patients receiving St. Jude Medical prosthetic valves, we found that valve area index can be used as an independent variable in the regression estimator. Two digressions from the standard assumptions used in linear regression, heteroscedastic trend of the error term and outliers were found in the data set. Iteratively reweighted least square (IRLS) was adopted to handle heteroscedasticity. Influence function approach was used to evaluate the sensitivity of outliers in regression estimator. Under an equal response rate mechanism, IRLS not only solves the problem of heteroscedasticity, but is also less sensitive to outliers.     

Disturbances of Pulmonary Function in Mitral Valve Disease

To study the sequence of changes in respiratory function that occur in the natural history of mitral stenosis, and the physiological basis of “cardiac dyspnea”, 30 patients with chronic mitral valve disease were subjected to detailed pulmonary function tests. There was no significant change in vital capacity and functional residual capacity. The reduction in maximal mid-expiratory flow rate showed excellent correlation with the respiratory symptoms. The pulmonary capillary blood volume was increased in moderately advanced cases but was consistently reduced in the severest cases. Hyperventilation was due to an increased respiratory rate. Dyspnea was associated with increased respiratory work owing to the interrelation between the reduction in diffusion capacity, compliance, cardiac output, the increase in airway resistance, and the uneven ventilation and perfusion of the lungs. The amount of “effort” required to breathe is incommensurate with the external load in these patients.     

An evaluation of semiautomatic approaches to contour segmentation applied to fungal hyphae

Semiautomatic image analysis techniques are particularly useful in biological applications, which commonly generate very complex images, and offer considerable flexibility. However, systematic study of such methods is lacking; most research develops fully automatic algorithms. This paper describes a study to evaluate several different semiautomatic or computer-assisted approaches to contour segmentation within the context of segmenting degraded images of fungal hyphae. Four different types of contour segmentation method, with varying degrees and types of user input, are outlined and applied to hyphal images. The methods are evaluated both quantitatively and qualitatively by comparing results obtained by several test subjects segmenting simulated images qualitatively similar to the hyphal images of interest. An active contour model approach, using control points, emerges as the method to be preferred to three more traditional approaches. Feedback from the image provider indicates that any of the methods described have something useful to offer for segmentation of hyphae.     

Total Replacement of the Mitral Valve: Results of Insertion of a Starr-Edwards Valve in Five Patients

In five patients the mitral valve was resected and total valve replacement undertaken. The Starr-Edwards prosthesis was inserted. The first patient died, two and one-half months after operation, of a wide massive left-atrial clot and peripheral embolization. The second and third patients are well and back at work at eight months after operation, and the fourth patient is well at two and one-half months after operation. The fifth patient died suddenly at three weeks from massive peripheral embolization originating from the left side of the heart. The technical details of the insertion of the valves are described and the importance of careful postoperative anticoagulant management is stressed.     

二尖瓣置换术后左心室破裂2 例并文献复习

目的:总结二尖瓣置换术后左心室破裂2例临床经验教训,方法:回顾性分析我院2006,1-2009,12二尖瓣置换术后左心室破裂2例的临床资料,两例均在监护室里发生突然大出血,紧急输血,输液,机械呼吸,抗休克治疗,并行开胸手术。结果:一例心外修补抢救成功,术后2周顺利出院,一例CPB下心内外修补,因低心排综合症死亡。结论:左心室破裂是二尖瓣置换术最严重的并发症,一旦发生死亡率极高,因此预防,避免其相关因素更关键。     

Severity of Mitral Valve Degeneration Is Associated with Chromosome 15 Loci in Whippet Dogs

Mitral valve degeneration (MVD) is the most common form of heart disease in dogs, frequently leading to left-sided congestive heart failure and cardiac mortality. Although breed-specific disease characteristics and overrepresentation point towards a genetic origin for MVD, a causative mutation and complete molecular pathogenesis are unknown. Whippet dogs are overrepresented in incidence of MVD, suggesting an inherited component in this breed. Expressivity of this condition is variable with some dogs showing evidence of more severe disease at earlier ages than other dogs. This phenomenon makes a traditional case versus control genetic study prone to phenotyping error. This study sought to avoid these common pitfalls by identifying genetic loci associated with severity of MVD in Whippets through a genome-wide association study (GWAS). 138 Whippet dogs were characterized for MVD by echocardiographic examination and a novel disease severity score was developed and adjusted for age in each subject. Single nucleotide polymorphism (SNP) genotype data (170k Illumina CanineHD SnpChip) was obtained for DNA isolated from blood of each study subject. Continuous variable genome wide association was performed after correction for population stratification by efficient mixed model association expedited (EMMAX) in 130 dogs. A genome wide significant association was identified on chromosome 15 (peak locus 57,770,326; P_adj = 0.049) and secondary loci of suggestive association were identified on chromosome 2 (peak locus 37,628,875; P_adj = 0.079). Positional candidate genes were identified within the primary and secondary loci including follistatin-related protein 5 precursor (FSTL5) and Rho GTPase-activating protein 26 (ARHGAP26). These results support the hypothesis that severity of MVD in whippets has a genetic basis and warrants further study by either candidate gene sequencing or next-generation techniques.     

On the Presence of Affine Fibril and Fiber Kinematics in the Mitral Valve Anterior Leaflet

In this study, we evaluated the hypothesis that the constituent fibers follow an affine deformation kinematic model for planar collagenous tissues. Results from two experimental datasets were utilized, taken at two scales (nanometer and micrometer), using mitral valve anterior leaflet (MVAL) tissues as the representative tissue. We simulated MVAL collagen fiber network as an ensemble of undulated fibers under a generalized two-dimensional deformation state, by representing the collagen fibrils based on a planar sinusoidally shaped geometric model. The proposed approach accounted for collagen fibril amplitude, crimp period, and rotation with applied macroscopic tissue-level deformation. When compared to the small angle x-ray scattering measurements, the model fit the data well, with an r² = 0.976. This important finding suggests that, at the homogenized tissue-level scale of ∼1 mm, the collagen fiber network in the MVAL deforms according to an affine kinematics model. Moreover, with respect to understanding its function, affine kinematics suggests that the constituent fibers are largely noninteracting and deform in accordance with the bulk tissue. It also suggests that the collagen fibrils are tightly bounded and deform as a single fiber-level unit. This greatly simplifies the modeling efforts at the tissue and organ levels, because affine kinematics allows a straightforward connection between the macroscopic and local fiber strains. It also suggests that the collagen and elastin fiber networks act independently of each other, with the collagen and elastin forming long fiber networks that allow for free rotations. Such freedom of rotation can greatly facilitate the observed high degree of mechanical anisotropy in the MVAL and other heart valves, which is essential to heart valve function. These apparently novel findings support modeling efforts directed toward improving our fundamental understanding of tissue biomechanics in healthy and diseased conditions.