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1.
The correlation between echocardiographically and angiographically calculated ejection fraction and systolic excursion of the mitral annulus was studied in 81 patients. Knowing that the mitral annulus changes its size, shape, and position during the cardiac cycle, the authors measured systolic excursion of the annulus by 2D echocardiography. Displacement of the mitral annulus was measured from four different points (medial, lateral, anterior, posterior) by apical four-chamber and apical two-chamber approaches. Patients with and without regional wall motion abnormalities were included. Left ventricular volumes and ejection fraction (EF) were calculated in the standard manner introduced by Teichholz et al and also with biplane left ventriculography. As a result, EF calculated by cineangiography, was moderately correlated with the Teichholz method (r = 0.66) while it was highly correlated with measurements of mitral annular motion (MAM) (r = 0.87). The correlation can be expressed by the regression equation, EF (angiography) = 5.7 MAM (in mm) -6.5. They conclude that measurements of annular motion is an easy and reliable index of left ventricular function as an alternative to traditional methods.  相似文献   

2.
We report two patients with reentrant atrial tachycardia that originated at the AV annulus. Atrial tachycardia originated in the posterior portion of mitral annulus in one patient (case 1) and the posterolateral portion of tricuspid annulus in one patient (case 2). Tachycardia was successfully eliminated by RF catheter ablation in both patients, with the catheter placed underneath the mitral valve in case 1 and on the tricuspid annulus in case 2. Spiky potentials were recorded in the diastolic phase of the atrium during tachycardia at the sites of successful ablation. Spiky potentials were also recorded after atrial electrogram during sinus rhythm, and showed decremental properties during atrial pacing. An accelerated atrial rhythm was observed during RF application, and tachycardia could not be induced after ablation in either patient. Tachycardia in these patients seemed to be due to reentrant tachycardia originating in the accessory AV node (Mahaim fiber) without ventricular connection.  相似文献   

3.
M-mode and two-dimensional echocardiographic images were obtained using the planimeter method in the short axis view and calculated by Doppler-derived pressure half-time in 24 patients with mitral stenosis before and after surgical commissurotomy and posterior annuloplasty. The diameter of the mitral valve annulus was measured in the standard long axis view and in the apical four-chamber view using two-dimensional echocardiography. Preoperatively, the mitral annulus was dilated in all patients as a consequence of left atrial dilation. This could be one of the factors causing residual regurgitation after surgical mitral commissurotomy. However, more data are needed to demonstrate that annuloplasty can prevent the development of mitral regurgitation after surgery.  相似文献   

4.
OBJECTIVES: The purpose of this study was to characterize anisotropy in the triangle of Koch by relating electrophysiology with anatomy. BACKGROUND: Atrioventricular (AV) node fast and slow pathway characteristics have been suggested to be due to nonuniform anisotropy in the triangle of Koch. METHODS: During atrial pacing, we determined the electrical activity within the triangle of Koch by multichannel mapping in 11 isolated hearts from pigs and dogs. Orientation of fibers was determined in nine hearts. RESULTS: Fibers were parallel to the tricuspid valve annulus (TVA) in the posterior part of the triangle of Koch. In the midjunctional area, the direction of the fibers changed to an orientation perpendicular to the TVA. During stimulation from posterior and anterior sites, activation proceeded parallel to the TVA at a high conduction velocity (0.5 to 0.6 m/s). During stimulation from sites near the coronary sinus, a narrow zone of slow conduction occurred in the posterior part of the triangle of Koch where activation proceeded perpendicular to the fiber orientation. Above and below this zone, conduction was fast and parallel to the annulus. After premature stimulation, conduction delay in the triangle of Koch increased by 4 to 21 ms; in contrast, the AH interval increased by 80 to 210 ms. CONCLUSIONS: Data support the concept of anisotropic conduction in the triangle of Koch. Activation maps correlated well with the arrangement of superficial atrial fibers. Comparison of conduction delay in the triangle of Koch and AH delay after premature stimulation disproves that anisotropy in the superficial layers plays an important role in slow AV conduction.  相似文献   

5.
During a 10-year period, we have encountered 6 patients (mean age, 61.2 years) with left ventricular rupture following mitral valve replacement, with an overall incidence of 1.8 percent. Four patients had early rupture, one had delayed rupture, and one had late rupture with a false aneurysm formation. Among four patients with early rupture, there were two patients with external repair by using a large ventricular patch and two patients with internal and the external repair by removing the prosthetic valve and patching both the inside and outside of the ventricle. In a patient with delayed rupture, bleeding from an epicardial hematoma was recognized along the atrioventricular groove in the intensive care unit. It was possible to control bleeding by packing the gauze, hemostatic cellulose [Surgical], and fibrin glue. Late rupture was recognized as a false aneurysm; however, there were no clinical symptoms. All patients survived the surgery, but two patients with early rupture subsequently died. One of these died of renal failure and the other died of multiple organ failure. The sites of rupture in all patients were in accordance with type 1 rupture (Treasure's classification); however, an autopsy review demonstrated the initial laceration in one case was recognized in the membranous septum 5 mm below the mitral ring and extended to the posterior atrioventricular groove. These findings suggest that the injury in the anterior mitral annulus could lead to type 1 rupture, although in the posterior mitral annulus more commonly. Since 1987, we have preserved the posterior leaflet with attached chordae when the mitral valve was fragile and myxomatous. As a result, no instances of left ventricular rupture were encountered.  相似文献   

6.
Posteromedial retraction of the tympanic membrane, between the oval window superiorly and the round window niche inferiorly, results in the formation of an epithelium-lined pocket within the sinus tympanic recess. Failure to recognize posterior invagination of the tympanic membrane intraoperatively leads to inadvertent tearing of the tympanomeatal flap at the level of the annulus with epithelial seeding of the middle ear and probably cholesteatoma recurrence. This article focuses on the clinical manifestations and radiographic findings suggestive of sinus tympanic epithelial retraction of the pars tensa and provides direct correlation between human cross-sectional temporal bone anatomy and otomicroscopy. The surgical management of these challenging lesions includes initial endaural access, external meatal bone removal posteromedial to the tympanic annulus and anterior to the vertical portion of the facial nerve, and middle ear ventilation after marsupialization of the epithelial retraction. Although early tympanic membrane retraction can be treated with a ventilation tube, deep epithelial pockets may require additional surgical treatment. A method for the management of sinus tympanic cholesteatomas is demonstrated.  相似文献   

7.
OBJECTIVES: This study sought to present evidence that fast atrioventricular (AV) node pathways with posterior exit sites may participate in typical AV node reentry. BACKGROUND: Catheter ablation of the slow AV node pathway in the posteroseptal right atrium is the preferred therapeutic approach in patients with AV node reentrant tachycardia. Despite the success achieved with this approach, electrophysiologic changes consistent with fast pathway ablation are occasionally observed. One potential explanation is the presence of an aberrant posterior fast pathway. METHODS: The location of fast and slow AV node pathways was determined by atrial activation mapping along the tricuspid valve annulus during tachycardia and was further confirmed by the effect of radiofrequency catheter ablation. RESULTS: Seven patients with AV node reentrant tachycardia had evidence of a posterior fast pathway near the coronary sinus os. Abolition of anterograde and retrograde fast pathway conduction followed radiofrequency ablation in the posteroseptal region in six patients. Consistent with fast pathway ablation, the AH interval increased from 70 +/- 24 to 195 +/- 35 ms (mean +/- SD), and tachycardia was no longer inducible. Selective slow pathway ablation was performed in one other patient with a posterior fast pathway. CONCLUSIONS: Functionally fast AV node pathways may be located in the posteroseptal right atrium, where slow pathway modification is performed. These data delineate the limitation of an anatomically guided slow pathway ablative approach and emphasize the importance of detailed mapping and localization of the retrograde fast pathway exit site before ablation. Failure to recognize the presence of posterior fast AV node pathways may account for sporadic examples of AV block, complicating posteroseptal ablation in patients with AV node reentry.  相似文献   

8.
We have carried out an experimental investigation of lesions of the intervertebral disc produced by flexion, lateral bending and rotational forces in an attempt to produce disc herniations. Adult Wistar rats were divided into 4 groups: control and posterior, lateral and rotational herniation. There were 10 rats in each group. The tail between the 5th and 8th vertebral segments was used. A Kirschner wire was inserted into each of 2 adjacent vertebrae and the movement produced had an apex which was anterior or lateral depending on the group involved. Variables such as rupture of the annulus, the cellularity of the nucleus pulposus and the site of the lesion in the disc were studied histologically. The height of the disc, the protrusion, the thickness, and the surfaces of the annulus fibrosus and the nucleus pulposus were measured. In every case we found a nuclear displacement which did not become a protrusion. The surface parameters and the cellularity of the nucleus pulposus are most useful indicators and should be included in any study examining the disc after the injection of substances for treatment.  相似文献   

9.
To allow remodeling of the annulus while respecting natural three dimensional annular movements during mitral valve repair, a new annuloplasty ring (St Jude Medical [SJM]-Séguin annuloplasty ring) was developed. This ring has variable flexibility; that is, it is sufficiently rigid on the anterior portion to maintain intercommissural distance, and sufficiently flexible on the posterior portion to respect left ventricular function and natural three dimensional annular mobility. Fifty patients operated on for pure mitral regurgitation between January, 1994 and June, 1995 were studied. Mean age was 58 years. The cause of mitral insufficiency was degenerative in 80% of the patients, rheumatic in 12%, ischemic in 4%, and infectious in 4%. The operative technique to restore normal valve coaptation was quadrangular resection in 31 cases, commissurotomy and chordal fenestration in 8, use of polytetrafluoroethylene chordae in 6, and chordal shortening or transposition in 5. Annuloplasty with a SJM-Séguin annuloplasty ring was realized in all 50 cases. Transesophageal echocardiographic mitral regurgitation decreased from 3.6 +/- 0.8 to 0.3 +/- 0.2 after repair (p < 0.005). Two post operative deaths due to non valve related complications, were observed. There were no ring related complications, especially no left ventricular outflow tract obstruction due to systolic anterior motion. Patients were all reviewed at a mean follow-up of 12.1 months (range, 9-27 months). All are well, in New York Heart Association functional Class I. Echocardiography showed a mean 0.4 +/- 0.3 mitral regurgitation, absence of any systolic anterior motion, and satisfactory mobility of the annuloplasty ring after the movements of the natural annulus, including non planar deviation. These preliminary results suggest that this annuloplasty ring 1) provides excellent correction of annular dilatation and remodeling of the annulus, 2) avoids systolic anterior motion observed with rigid rings, and 3) preserves physiologic three dimensional annulus motion.  相似文献   

10.
1. The maintenance of the nucleus pulposus matrix in the adult human disc is dependent on the functional integrity of the cartilage end plate cells. 2. Cartilage end plate senescence is followed by compensatory cartilaginous metaplasia of annulus fibrosus cells. 3. It is proposed that disc narrowing and collapse are related to metabolic failure of matrix production by end plate and annulus fibrosus cells. 4. Calcium pyrophosphate dihydrate crystal deposits, a visible manifestation of a metabolic abnormality, are found frequently in the annulus fibrosus and cartilage end plates of elderly patients with degenerative disc disease.  相似文献   

11.
Observers tracked binocular rivalry between a pair of small, foveally viewed gratings whose orientation differed between the 2 eyes. In Exp 1, a textured annulus surrounding 1 eye's grating increased the total duration of exclusive visibility of the grating only when the grating-annulus separation was less than 0.5°. In Exp 2, observers tracked the visibility of a monocular annulus that surrounded a foveally viewed grating that was either engaged in rivalry or fused with a grating alone viewed by the other eye. The visibility of the annulus was greater when the grating it surrounded was not undergoing rivalry fluctuations. In Exp 3, the predominance of a rival grating was greater when the contours in the surrounding annulus were orthogonal to those of the rival grating. In Exp 4, total exclusive visibility of a given grating-annulus target was greater when the grating and the annulus contained the same orientation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

12.
The technique of tricuspid valve repair with the Cosgrove-Edwards Annuloplasty System is described. This system provides a measured plication of the tricuspid valve annulus with a technique that is easily reproducible and permits physiologic motion of the tricuspid annulus.  相似文献   

13.
Mitral annulus anatomy and dynamics were evaluated in 12 subjects using a three-dimensional transesophageal echocardiographic technique. The mitral annular area, diameters and distance from the left ventricular apex were measured in end-diastole, mid-systole, end-systole and mid-diastole. The mitral annulus had its largest area in end-systole and the smallest area in end-diastole. The shape of the annulus changed during the cardiac cycle with the maximal change occurring in the diameters passing close to the middle of the mitral leaflets. In the vertical plane, the annulus had a shallow ski-slope shape, with the attachment of the anterior leaflet being farthest from the apex. In other words, the highest point of the annulus was situated anteromedially and was visualized in the long axis imaging plane.  相似文献   

14.
The sperm plasma membrane is segregated into functionally, biochemically, and structurally distinct domains yet the protein sorting pathways and assembly mechanisms that assemble these domains during spermiogenesis are incompletely understood. We previously characterized two structurally related size-variant, integral membrane proteins of 52 kDa (PM52) and 35 kDa localized to the periacrosomal plasma membrane of guinea pig cauda epididymal spermatozoa (Westbrook-Case et al., 1994). In this study we used light and electron microscopic immunocytochemistry to define the expression pattern and sorting pathway that establishes the domain-specific distribution of PM52 during spermiogenesis. The PM52 is first expressed in acrosome-phase spermatids and it localizes exclusively to the cytoplasmic lobe. Immunoelectron microscopy revealed that both cytoplasmic vesicles and the plasma membrane of the cytoplasmic lobe labeled with anti-PM52. During early stages of expression, PM52 appeared to be absent from the head region, but significant PM52 accumulation over the spermatid head was noted in late acrosomal phase spermatids. Throughout spermiogenesis PM52 extended posteriorly to the annulus, which represents a barrier preventing PM52 diffusion into the posterior tail. Following the migration of the annulus to the midpiece-principal piece junction, PM52 began to disappear from the flagellar region and at the completion of spermiogenesis most of the PM52 was restricted to the acrosomal segment. Spermatids and epididymal sperm PM52 exhibited identical sizes by SDS-PAGE and immunoblotting, indicating that they are not proteolytically modified during epididymal maturation. The PM52 antibodies were also used to screen a guinea pig testis cDNA library, and sequence determination of full-length PM52 clones demonstrated identity of a sperm membrane protein recently termed "sperad" (Quill and Garbers, 1996). Membrane barriers and potential mechanisms establishing the domain-specific residence of PM52 are discussed.  相似文献   

15.
The nonlinear three-dimensional poroelastic creep response of a lumbar motion segment under a constant axial compression (400, 1200, or 2000 N) is investigated for a period of 2 h. The role of facet joints, strain-dependent variable permeability, boundary pore pressure, and coupled sagittal rotation on response is studied. Biomechanics of annulus excision, nucleotomy, and facetectomy are also investigated. Both material and geometric nonlinearities are considered. The annulus bulk is modelled as a nonhomogeneous composite of collagenous fibers and annulus bulk. As time progresses, axial displacement increases, pore pressure decreases, annulus bulk undergoes larger compressive stresses, fiber layers become slack, and facets carry larger loads. Surgical alterations markedly soften the temporal response and increase facets forces. In contrast, the strain-dependent variable permeability and boundary pore pressure stiffen the response and decrease forces on the facets. Changes in the nucleus fluid content, facet joints, boundary pore pressure, and disc permeability markedly influence the lumbar biomechanics.  相似文献   

16.
An analysis of three-dimensional movement of the mitral valve annulus (MVA) may address the question of geometrical change after mitral valve repair to preserve mitral annular function. Conventionally, annular contraction has been studied for this purpose. We investigated this geometrical change occurring in the anterior half of the MVA and discuss its clinical significance. Three-dimensional images of the MVA during systole were reconstructed from magnetic resonance images of eight normal subjects. The posterior half of the MVA exhibited translational motion. We assume that this portion, exhibiting translational motion as well as contraction, purely follows the motion of the left ventricular contraction. Compensating for the discrepancy between the motion of the aortic root and that of the posterior half of the MVA, the anterior half exhibited a flexible change in shape during systole, thus maintaining a sufficient left ventricular outflow tract (LVOT). The increase in the extent of displacement of the anterior MVA from the posterior half of the MVA during systole, which was 3.6 +/- 1.0 mm (mean +/- SD), indicates the annular flexibility. The preservation of annular flexibility may prevent LVOT obstruction. Further geometrical analysis of patients after mitral repair will clarify annular function as presented in this article.  相似文献   

17.
Homograft aortic root replacement was done to three patients and the anterior mitral leaflet of the homograft was used with success in all cases. Case 1. A 37-year-old man had late-onset active prosthetic valve endocarditis with a fistula from the aortic annulus to the left atrium. The fistula was closed by using a homograft anterior mitral leaflet and the aortic root was replaced by a homograft with reimplantation of the coronary arteries. He is very well without evidence of recurrent endocarditis 29 months after the operation. Case 2. A 37-year-old man had early-onset active prosthetic valve endocarditis and developed the same fistula as case 1. He was treated successfully as in case 1. He is very well 4 months after the operation. Case 3. A 50-year-old woman, who had undergone aortic commissurotomy due to aortic valvular stenosis fifteen years before, deteriorated again. She had subvalvular membranous stenosis and a small aortic annulus. Konno-Soma procedure was applied to enlarge the annulus and the aortic root was replaced by a homograft. The interventricular septal incision was closed successfully with use of the anterior mitral leaflet of the homograft. Homograft aortic root replacement was an attractive procedure for prosthetic valve endocarditis or a small aortic annulus, and the homograft anterior mitral leaflet was useful for closing the fistula due to the infection and for closing the interventricular septal incision of Konno-Soma procedure.  相似文献   

18.
The development of fibrocartilage in rat lumbar intervertebral discs has been correlated with an immunohistochemical analysis of the changing distribution of extracellular matrix components. Disc anlagen were first recognised by embryonic day 14 as segmental cell condensations. By E16, the notochord formed a series of bulges, each representing a future nucleus pulposus, and the annulus fibrosus had differentiated in the disc anlagen. The inner part of the annulus was composed of cartilage which linked that of adjacent vertebral bodies. The outer part was fibroblastic, with layers of parallel fibroblasts. The long axes of the cells in successive layers lay at an angle of approximately 90 degrees to each other. This criss-cross orientation of cells preceded the oriented deposition of collagen fibres to form the lamellae. Disc anlagen were immunolabelled weakly for types I and III collagen, chondroitin 6-sulphate and dermatan sulphate. Later tissue differentiation was marked by the appearance of type II collagen, chondroitin 4-sulphate and keratan sulphate in the inner annulus. These components also appeared in the outer annulus, but only in adult animals, and indicated metaplastic change in the lamellar fibroblasts. Fibrocartilage in the nucleus pulposus was only seen in old animals, and the origin of the tissue was less clear. However, the fibrocartilage cells appeared to be derived from the cartilage end plate and/or from the inner annulus. We conclude that fibrocartilage in the intervertebral disc is derived from several sources and that the radial distribution patterns of extracellular matrix components in the adult disc are explained by the embryonic origins of its parts.  相似文献   

19.
20.
BACKGROUND: Aortic annulus enlargement has long been advocated for the placement of valve prostheses larger than otherwise would have been possible. Little information exists, however, on the short- and long-term outcome of this surgical procedure. METHODS: We performed a retrospective review of 530 patients enrolled in a registry for patients who underwent aortic valve replacement using the Hancock II bioprosthesis and were followed up prospectively over the course of 11 years at a single institution. In an effort to avoid prosthetic valve-patient mismatch, the aortic annulus was enlarged in 98 patients (18%). Short- and long-term outcome was analyzed. RESULTS: Enlargement of the aortic annulus during aortic valve replacement increased the operative mortality rate from 3.5% to 7.1%, but this difference did not reach statistical significance (p = 0.10). The long-term survival of patients who had annulus enlargement was similar to that of patients who did not. Because there were differences in the clinical profile of patients who had annulus enlargement and those who did not, a case-control study was carried out. This study showed similar long-term survival, freedom from valve-related and cardiac death, and combined end points in the two groups of patients. CONCLUSION: Aortic annulus enlargement increased the operative mortality of aortic valve replacement. However, patients who underwent enlargement of a small aortic annulus had long-term survival and freedom from cardiac and valve-related death comparable to those of patients who received larger aortic prostheses.  相似文献   

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