Mid-diastolic aortic valve opening in bacterial endocarditis of aortic valve

Echocardiographic features of acute aortic regurgitation resulting from bacterial endocarditis have been well documented (Nathan et al., 1980; Weaver et al., 1977; Wray, 1975a), and include thick shaggy echoes from aortic valve in diastole, fine diastolic flutter of aortic valves suggestive of rupture of cusps, and premature closure of mitral valves. Echocardiography being a sensitive noninvasive technique for detecting aortic valve vegetations is heavily relied on for earlier diagnosis and prompt therapy of these patients. Prognosis of echocardiographically positive endocarditis is known to be worse than for echo-negative patients. The following case is being presented because of an unusual echocardiographic manifestation with mid-diastolic aortic valve opening secondary to flail aortic valve from staphylococcal endocarditis of the aortic valve.     

热风阀阀板的流场分析

以COSMOSFloworks软件为工具,对国内某重工集团的DNI1800热风阀阀板水道进行了流场分析.分析结果表明:阀板内水速分布不均匀,是造成阀板换热不均,局部急冷急热的重要原因.应改变此型阀板中部流态和加宽内水环边缘水冷结构来改善冷却均匀性,以达到提高阀板寿命的目的.     

Mitral valve myxoma

Cardiac myxomas arising from the mitral valve are extremely rare. We describe the case of an asymptomatic 49-year-old woman who was found to have a 3.6 x 4.0-cm myxoma originating from the atrial side of the anterior mitral leaflet. The lesion was successfully treated by surgical excision and mitral valve replacement. A review of the literature regarding this rare lesion is presented.     

Continent valve ileostomy

2 years of experience with the sphincteroplasty in colostomy as well as intensive histological studies have shown that gastrointestinal smooth muscle can be autotransplanted without loosing functional or histological integrity. The following conclusions are based on experimental studies in dogs: (1) the sphincteroplasty technique can be successfully applied in ileostomy, and (2) the sphincteroplasty must, however, be combined with a pre-sphincter valve and an omega loop with Braun's anastomosis. The first clinical results confirm this concept.     

Quadricuspid aortic valve

Generalizability of findings is a critical issue in research on pregnancy and work. The characteristics of a sample of 350 pregnant military women were compared with those of the populations of active duty women and active duty pregnant women. The sample was fairly representative in terms of minority status and age. The sample differed somewhat in terms of branch of service, rank, and marital status. Comparisons of demographics and pregnancy planning between military and civilian pregnant women supported generalizability. Unique aspects of military service and different access to health care among civilian pregnant women warrant caution in generalizing of findings.     

Prosthetic valve endocarditis leading to valve replacement: a case study

Infective endocarditis (IE) is a pathologic condition of native or prosthetic heart valves or endocardium, which may result in valve destruction and congestive heart failure. It occurs more frequently in men than in women, and there is an increased trend in the elderly. The following conditions predispose patients to IE: congenital and rheumatic heart disease, calcification or stenosis of a valve, prosthetic valve surgery, a previous episode of endocarditis, poor dentition, parenteral drug abuse, and placement of intravascular lines or devices. Effective treatment frequently involves a combination of intense antibiotic therapy and surgical repair. Risk of death from IE is related to age over 60, diagnosis of staphylococcal infection, involvement of an aortic or prosthetic valve, and the presence of any of the following sequelae of endocarditis: congestive heart failure, embolic phenomenon, and neurologic deficit. Clinicians should suspect endocarditis in patients presenting with fever of unknown origin and who are at risk for endocarditis. Timely evaluation with transthoracic or transesophageal echocardiography may identify patients in the early stages of endocarditis and direct the patient to definitive therapy. Early treatment of native and prosthetic valve endocarditis may decrease its overall morbidity and mortality. This case study illustrates some of the challenges in effectively managing prosthetic valve endocarditis.     

Mid-term surgical results after valve replacement with the CarboMedics valve prosthesis

Located at the level of the Z-line, the transverse cytoskeletal network of insect-flight muscle interconnects adjacent myofibrils with one another, and interconnects peripheral myofibrils with the cell membrane. This network has been presumed to keep myofibrils in register, or to distribute tension laterally among myofibrils. In this study, we used scanning-electron microscopy to reveal details of the three-dimensional arrangement of this network. The network is seen to interconnect longitudinal elements of the cytoskeletal network which surround each myofibril. The arrangement is not unlike that seen in vertebrate skeletal muscle. Interestingly, the transverse network makes contact with cell components such as dense bodies and mitochondria. Such contacts imply potential roles over and above those noted above. The network may be involved not only in mechanical function, but possibly also in intracellular communication.     

Thirty years experience with heart valve surgery: isolated mitral valve replacement

BACKGROUND: Thirty years have elapsed since the commencement of open-heart surgery in South Australia. A retrospective study was performed to evaluate mortality and complication rates and to identify factors associated with poor outcomes in all patients who underwent prosthetic mitral valve replacement during this period. METHODS: Questionnaires and personal contact have been used to generate a combined database of pre-operative and post-operative information and long-term follow-up on 938 patients who underwent isolated prosthetic mitral valve replacement at the Cardio-Thoracic Surgical Unit of the Royal Adelaide Hospital between 1963 and 1993. RESULTS: Complete survival follow-up data were obtained for 92% (865) of the patients. The Starr-Edwards valve was used in 95% (891) of the patients, a Bjork-Shiley prosthesis in 2.5% (23) of the patients, and only 24 (2.5%) other valves were inserted. The hospital mortality rate for the 30-year period was 4.7%. The mean age of the patients who underwent surgery was greater in each of the three successive decades. A long-term survival advantage was observed for patients with mitral stenosis, however, survival was significantly shorter for patients with higher New York Heart Association (NYHA) functional classifications and for patients in pre-operative atrial fibrillation. Pre-operative dyspnoea was significantly improved following mitral valve replacement. The rates of postoperative haemorrhagic and embolic complications were low by comparison with other published series. CONCLUSION: Mitral valve recipients do not regain a normalized life expectancy, but risk factors that determine long-term survival can be identified pre-operatively to aid appropriate patient selection.     

阀门定位器阀位检测与压电阀驱动电路设计

本文主要介绍定位器两大模块:阀位检测电路模块与压电阀驱动电路模块进行详细的硬件设计,电路都是针对检测或驱动对象的特性展开设计的,通过理论分析与电路测试证明两大模块的电路设计方案可行性较好。     

Mitral valve replacement with total preservation of native valve and subvalvular apparatus

BACKGROUND AND AIMS OF THE STUDY: Preservation of the mitral valve and subvalvular apparatus was introduced clinically in the early 1960s, but for two decades the technique for mitral valve replacement included excision of both leaflets and their attached chordae tendineae. Lately, emphasis has been replaced on retaining the mitral subvalvular apparatus during valve replacement because of its role in left ventricular function. Hence, during the past six years, when performing mitral valve replacement we have, when possible, preserved the valvular and sub-valvular mitral apparatus. METHODS: Between January 1990 and November 1996, complete retention of all mitral tissue in connection with mitral valve replacement was performed in 58 patients (23 women and 35 men). Mean age was 63 years (range: 23 years to 77 years). Coronary bypass was a concomitant procedure in 19 patients; both the mitral and aortic valve was replaced in four cases. Calcified and/or stenotic valves were not a contraindication for the procedure; calcified plaques were removed. Adhesion between anterior and posterior leaflets was treated with sharp dissection. Valve and subvalvular tissue were preserved. The leaflets were reefed within the valve-sutures and compressed between the sewing ring and the native annulus when implanting the valve prosthesis. Chordal tension on the ventricle is thus maintained and the chordae pulled away from the valve effluent. RESULTS: Six patients died in the postoperative period and three had transient neurological symptoms. In no patient was death or transient neurological symptoms a consequence of the retention of mitral leaflets with subvalvular apparatus. CONCLUSIONS: We find the described technique to be useful not only in valve insufficiency but also in valve stenosis when preserving the mitral leaflets with sub-valvular apparatus during valve replacement. The technique is without procedure-related complications and prevents obstruction of left ventricular outflow tract.