超声引导心脏靶点起搏和精确消融的初步实验研究

目的 初步建立超声引导监控下的心脏传导系统的靶点起搏和精确消融方法。方法 12只杂种犬急性开胸模型，经颈静脉插入超声导管分别进入上腔静脉，右心房，室或经心脏表面进行心脏扫描，获取并确认心脏传导系统超声解剖结构标志及其心肌激动顺序，确定靶组织空间益关系，引导经股静脉插入的心脏起搏或消融导管和经心脏表面插入的穿刺针到达靶组织并确认心内膜面接触，进行靶点起搏，精确射频及化学消融，超声实时监控全过程，对心脏离体标本进行病检和切片，确认靶点起搏位置，观察消融和起搏对心脏传导系统和组织细胞的损害。结果 超声能够在观察到心脏传导系统重要靶点部位，解剖结构的同时评价其结构内心肌激动的起始和传导顺序，能引导介入导管准确到达靶点组织，监控电极与心内膜央的接触，监控穿刺针在靶点组织内的准确空间位置，避免损伤冠状动脉及传导组织，及时评价起搏和消融损伤效果。确定终止治疗时机并监控并发症的发生，病解和切片表明超声引导心脏射频和化学消融定位准确，效果肯定。结论 超声能够引导心脏介入导管和穿刺针进行心脏靶点起搏和精确消融，定点消融心肌，使起搏和消融治疗更为精确，该方法将为临床心脏电生理疾病的治疗提供一种全新的简便，准确技术方法和手段。     

超声心动图对62例房间隔缺损封堵术后心功能变化的评价

目的：应用超声心动图评价房间隔缺损(ASD)封堵术前后左、右心室功能的变化。方法：对62例成功施行经皮穿刺ASD封堵术的患者进行研究。所有患者在术前、术后1周及1个月分别进行超声心动图检查．观察心脏大小及功能的改变。结果：ASD封堵术后，左室舒张末期前后径、左室舒张末期容积、左室每搏量及左室射血分数增大，而左室收缩末期容积未见明显改变；右室舒张末期前后径、右室舒张末期容积、右室收缩末期容积、右室每搏量、右室射血分数及右室心肌工作指数均减小。结论：经皮穿刺ASD封堵治疗既可减轻右室容量负荷，改善右室功能，也可改善左室的收缩功能：超声心动图对ASD封堵前后心脏血流动力学评价及疗效的观察起了重要的作用。     

Non-invasive estimation of the diastolic elastic and viscoelastic properties of the left ventricle

The present study applies a non-invasive method to the quantitative evaluation of left ventricular stiffness in normal subjects and in patients with ischaemic heart disease (IHD). We have studied 20 patients with IHD and 25 healthy subjects. The third heart sound (S3) was detectable in all patients. We have correlated the energy spectrum of S3, divided into 15 Hz bands, with a series of echocardiographic parameters. The existence of a significant correlation between the spectrum energy and the diameter and thickness of the left ventricle at the moment of S3 allowed us to explore the possibility of interpreting the origin of S3 based on a mathematical model. Our hypothesis has been that, once the left ventricle starts vibrating, it behaves as a simple physical model composed of a mass and an elastic element. To this purely elastic model one can add a factor accounting for viscosity, with a damping effect, to obtain a more complex viscoelastic model. The stiffness coefficient 'k' was computed in both models from the peak frequency of S3 and the left ventricular mass at the moment of S3. Furthermore, in the viscoelastic model, the damping element 'c' was also computed. Both parameters--k and c--were significantly increased in the group with IHD compared with the control group. Although a simplification of the vibrating system, these models make it possible to obtain non-invasively information on the characteristics of the left ventricle through the combined use of echocardiography and spectral analysis of S3.     

Mitral insufficiency with congenital double-orifice mitral valve in an elderly patient.

We describe the case of a 79-year-old woman with mitral insufficiency and a double-orifice mitral valve (DOMV), discovered by echocardiography. Transthoracic echocardiography showed two insufficiency jets. Transesophageal echocardiography revealed a DOMV. Each orifice was provided with a subvalvular apparatus. No associated congenital abnormalities were present. Our case demonstrates that even in elderly patients with a double regurgitant jet, DOMV should be suspected and assessed by transesophageal echocardiography.     

Incremental Value of Three-Dimensional Echocardiography Over Transesophageal Multiplane Two-Dimensional Echocardiography in Qualitative and Quantitative Assessment of Cardiac Masses and Defects

In the present study, we compared three-dimensionally (3-D) reconstructed images with multiplane two-dimensional (2-D) transesophageal echocardiographic (TEE) images in 17 patients with various cardiac masses and defects. To overcome the problem of making measurements from 3-D reconstructed images, we carefully "dissected" the 3-D dataset using paraplane and anyplane 2-D sections, which were then used to obtain the maximum sizes of the cardiac masses and defects. Of the 15 vegetations and 9 abscesses detected by 3-D TEE in 7 patients, only 8 (53%) vegetations and 4 (44%) abscesses were detected by multiplane 2-D TEE (P < 0.02). Also, the exact anatomical location, shape, geometry, and extent of various cardiac masses and defects were more clearly delineated by 3-D than 2-D TEE. The maximum dimensions of cardiac masses and defects were larger by 3-D than by 2-D TEE in 17 (89%) of the 19 lesions available for comparison (P < 0.002). In addition, 3-D TEE correlated more closely than 2-D TEE when compared to surgical measurements in three patients in whom they were available. Thus, it would appear that in several instances, the exact size of the cardiac lesion could only be assessed by analysis of the 3-D volumetric dataset. Out preliminary study has demonstrated the superiority of transesophageal 3-D reconstruction over multiplane 2-D TEE in both qualitative and quantitative assessment of various cardiac mass lesions and pathological defects.     

超声心动图监测经导管心脏间隔缺损关闭术

应用超声心动图监测，经导管关闭先天性心脏间隔缺损９例。术中监测的主要内容有：（１）确定关闭器在心内的位置；（２）显示残余分流和瓣膜返流；（３）观察房间隔缺损球囊探测的过程。结果表明：超声心动图在显示心内结构、关闭器位置，残余分流和瓣膜流等方面有其独特性，同时可结合声学造影或术中需要进行多方面的监测。     

一种新的正交参数选优法及其在非线性回归分析中的应用

非线性回归分析是工程中经常采用的一种用来估计数学模型参数的方法，该方法能否顺利运用与参数初始值的选择有极大关系。本研究提出一种新的正交参数选优法——阻尼正交表法，它不仅可以保证非线性回归分析算法的顺利收敛，而且能够显著提高后者的收敛速度，进而极大改善非线性回归分析算法的应用性能。本研究的数值试验及心肌造影超声心动图定量分析应用实例表明，作为对传统正交参数选优法的一种改进，阻尼正交表法在科学与工程计算或信号与信息处理领域有着很好的应用前景。     

Two-dimensional echocardiography in the diagnosis of intracardiac masses: A prospective study with anatomic validation

The accuracy of two-dimensional echocardiography in the detection of intracardiac masses was verified in 334 patients who underwent cardiac catheterization in our laboratory over 21 consecutive months. A complete two-dimensional echocardiographic (2DE) examination was performed a day before catheterization. The presence or absence of a mass was verified at surgery in 77 patients who successively underwent mitral or aortic valve replacement (51), left ventricular aneurysmectomy with or without myocardial revascularization (25), and resection of atrial myxoma (2). In 32 patients 2DE revealed the presence of a mass-left or right atrial thrombi in 12, left atrial myxoma in 2, left ventricular thrombi in 16, and endocardial vegetations in 2. The other 45 patients were free of intracardiac masses on 2DE. Anatomic verification at surgery revealed the presence of an intracardiac mass in 34 patients. In 30 (true positives) of these, 2DE revealed the mass as well, and in 4 (false negatives) the presence of a mass had not been identified by 2DE. In 2 patients (false positives) the predicted mass was not found at surgery. Absence of a mass was correctly predicted by 2DE in 41 patients (true negatives). Thus 2DE detected intracardiac masses with sensitivity of 88.2% and a specificity of 95.3%. We recommend that 2DE be performed in all patients prior to hemodynamic study and/or cardiac surgery to enable safer management of patients with intracardiac masses during cardiac catheterization and/or cardiac surgery.     

Traumatic or septic aortic regurgitation: diagnosis by oesophageal echocardiography

Severe aortic regurgitation was discovered in a young man 21 days after blunt chest trauma and after a prolonged febrile state with positive blood cultures. Using transoesophageal echocardiography (TEE), it was possible to make the differential diagnosis between traumatic rupture and endocarditis as the cause of valvular insufficiency. The use of TEE in the initial evaluation of severe thoracic trauma with an unclear clinical picture is recommended. This method is easy to use at the bedside and gives precise information on the aortic valve and the ascending aorta.