[Mitral valve prolapse and cusp elasticity]. / Prolapso da valva mitral e elasticidade cuspidiana.

PURPOSE: To verify if systolic bulging of floppy mitral cusps can to elastic behavior of their myxomatous collagen tissue. METHODS: Five hearts with floppy mitral valves obtained from autopsies were distended with air (20 to 250 mmHg) through a catheter connected to the left ventricle. It was observed if some area of the atrial surface of the coapted cusps showed variable bulging according to the variation of air injection pressures. Molding of those surfaces (gypsum) allowed the same kind of analysis by other four researches. It was analyzed the cut surfaces of these radially sectioned molds. Lately, isolated tendinae chords were submitted to repeated tractions and observed if they exhibited elastic behavior. Histological study defined the presence of collagen myxomatous degeneration and quantified the amount of elastic tissue. RESULTS: In no case it was detected elastic bulding of mitral cusps. Cut surfaces of the molds confirmed that no increment of the prominent areas occurred, even in those regions with extensive, histologically confirmed, myxomatous substitution of the native collagen tissue. CONCLUSION: Increment of the degree of mitral bulging occurring during ventricular systole can not be ascertained to cusp elasticity but probably to papilar muscle traction.

[Relationship between volume reduction of the left ventricle and the increase of mitral valve prolapse. An experimental study in dogs]. / Relação entre redução volumétrica do ventrículo esquerdo e incremento do prolapso da valva mitral. Um estudo experimental em cães.

PURPOSE: To verify whether accentuated reductions of left ventricular volume lead to mitral valve prolapse. METHODS: Seven mongrel dogs were bled through the internal jugular vein, the systolic systemic pressure being kept between 100 and 140 mmHg by means of continuous infusion of dopamine; the inferior vena cava vein, in tree other dogs, was partially obstructed for 4 to 6 seconds; epicardial echocardiography was carried out in all cases. RESULTS: Reductions of volemia were about 50% of the estimated total blood volume. Systolic internal diameter of left ventricle decreased about 25% and systolic ostial diameter, about 12.5%. Three out of seven died suddenly from arrhythmia before one has reached a significant decrease in total blood volume; one showed momentary mitral valve prolapse, during a period of hypotension; however, this prolapse disappeared completely when systemic blood pressure was restored by increasing the dopamine dosage; one dog had slight systolic displacement of the anterior cusp toward left atrium (0.5mm) and the last two showed no change; one out of 3 dogs submitted to partial constriction of inferior vena cava had systolic displacement of anterior cusp of 1mm; in one case there was an equivalent degree of displacement of the anterior cusp toward the left ventricle and in the last one no change was detected. In all dogs there was a change in the dynamics of mitral valve closure: with accentuated reduction of left ventricular volume the posterior cusp became less mobile, the anterior cusp being the principal responsible for the systolic ostial occlusion. CONCLUSION: Accentuated reduction of dog's left ventricular volume does not, necessarily, cause mitral valve prolapse but only slight displacement of the anterior cusp toward the left atrium in some animals or no displacement at all.

[Necropsy study of the mitral valve according to 5 different echocardiographic planes]. / A valva mitral estudada por necrópsia segundo cinco diferentes planos ecocardiográficos.

PURPOSE: To study, in anatomic specimens, the regions of the mitral valve transected by the parasternal long axis, the apical five chamber, the apical four chamber, the apical two chamber and the left ventricle apical long axis echocardiographic views. METHODS: 15 patients' hearts, after fixation through intra-ventricular injection of formalin, were cut according to the five above referred echocardiographic views. RESULTS: Only the apical five chamber view studied adequately the most anterior regions of both mitral cusps. The apical four chamber and the parasternal long axis views examine the most posterior segments of the mitral valve. Heart sections made according to the apical two chamber view are not adequate to study both cusps on a anatomo-pathologic view. The left ventricle apical long axis is the one which better defines the length of both cusps. CONCLUSIONS: Its necessary to know precisely the regions of the mitral valve sectioned by different longitudinal echocardiographic views in order to visualize through that method localized mitral valve prolapse.

[Necropsy study of the mitral valve transected according to five echocardiographic planes]. / A valva mitral estudada à necrópsia segundo cinco diferentes planos ecocardiográficos.

PURPOSE: To study, in anatomic specimens, the regions of the mitral valve transected by the parasternal long axis, the apical 5 chamber, the apical 4 chamber, the apical 2 chamber and the left ventricle apical long axis echocardiographic views. METHODS: 15 patients' hearts, after fixation through intra-ventricular injection of formalin, were cut according to the five above referred echocardiographic views. RESULTS: Only the apical 5 chamber view studied adequately the most anterior regions of both mitral cusps. The apical 4 chamber and the parasternal long axis views examine the most posterior segments of the mitral valve. Heart sections made according to the apical 2 chamber view are not adequate to study both cusps on a anatomo-pathologic view. The left ventricle apical long axis is the one which better defines the length of both cusps. CONCLUSION: Its necessary to know precisely the regions of the mitral valve sectioned by different longitudinal echocardiographic views in order to visualize through that method localized mitral valve prolapse.

A histopathologic study of the mechanism of Evans blue staining of myocardial infarcts in rats.

In a study of the mechanism of Evans blue (EB) staining of experimental infarcts in rats, it has been reported that when the dye was injected iv before left coronary occlusion (LCO) it diffused centripetally from the periphery of the excluded vascular bed region (ExVB), i.e., the myocardial area with circulation interrupted by LCO, to its center. In the present study, we have attempted to identify the mechanism of this phenomenon. The animals were sacrificed at different times after EB injection, i.e., 10, 20, and 30 min and 1, 2.5, 4.5, 6, 16, 24 and 48 h. This phenomenon occurred from 4.5 up to 24 h after LCO and could not be ascribed to either collateral circulation or to venous backflow. We conclude that diffusion from one necrotic cell to another, beginning at the ill-perfused periphery of the ExVB (lateral and endocardial margins of the ExVB), and also at the epicardium (bathed by pericardial effusion rich in EB) is responsible for the production of the so-called "blue infarct".

A histopathologic study of the mechanism of Evans blue staining of myocardial infarcts in rats

In a study of the mechanism of Evans blue (EB) staining of experimental infarcts in rats, it has been reported that when the dye was injected iv before left coronary occlusion (LCO), it diffused centripetally from the periphery of the excluded vascular bed region (ExVB), i. e., the myocardial area with circulation interrupted by LCO, to its center. In the present study, we have attempted to identify the mechanism of this phenomenon. The animals were sacrificed at different times after EB injection, i.e., 10,20, and 30 min and 1,2,5, 4.5, 6, 16, 24 and 48 h. This phenomenon occurred from 4.5 up to 24 h after LCO and could not be ascribed to either collateral circulation or to venous backflow. We conclude that diffusion from one necrotic cell to another, beginning at the ill-perfused periphery of the ExVB (lateral and endocardial margins of the ExVB), and also at the epicardium (bathed by pericardial effusion rich in EB) is responsible for the production of the so-called "blue infarct"

[Communication between left atrium and venous coronary sinus associated with stenosis of the venous ostium and with stenosis the mitral valve. A case report]. / Comunicação entre átrio esquerdo e seio venoso coronário associado com estenose do óstio do seio coronário e com estenose da valva mitral. Relato de caso.

Woman, 76 years old with mitral stenosis died due to peripheral arterial embolism. The necropsy identified left atrial to coronary sinus fenestration associated with stenosis of the coronary sinus ostium and rheumatic mitral stenosis.

[Mitral valve prolapse in the 8th and 9th decades of life. Anatomo-pathologic study of 3 cases]. / Prolapso de valva mitral nas 8a. e 9a. décadas de vida. Estudo anátomo-patológico em três casos.

Different anatomo-clinic aspects from three mitral valve prolapse cases are compared to those commonly presented in the literature and are also utilized as a basis for a new classification of this disease. The patients are more than 77 years old, what is in contrast with the current concept of MVP as a disease of young-middle aged women. The first case shows marked ostial dilation and many ruptured chordae: as a consequence, this patient showed severe cardiac dysfunction. The anterior, rather than the posterior leaflet, presented intense myxoid degeneration. In the second case, no ruptured chordae were detected and, consequently, the degree of heart failure was lesser than the first one, in spite of the same degree of ostial dilation. Both leaflets showed the same degree of myxoid degeneration. The third patient, who does not have heart failure, showed myxomatous degeneration of both cusps, but no ostial dilation or chordal rupture were present. These aspects reinforce the impression that isolated mixomatous degeneration of the cusps is not so deleterious when compared to those cases where the mitral valvar ring is dilated or its chordae are also involved by that degenerative process. Therefore ostial dimension (normal or enlarged) and the state of the chordae (with or without rupture) appears to be important points to be considered in MVP.

[The mitral valve apparatus: an anatomo-echocardiographic approach]. / Aparelho valvar mitral: um enfoque anátomo-ecocardiográfico.

The shape of the mitral valve ring, the position of its chordae and of its leaflets were studied in 34 normal hearts fixed through intra-ventricular injection of tamponate formalin. As the authors have assumed that the post-rigor left ventricle has an architecture very similar to that seen at to the end of ventricular systole, comparisons were made between the anatomical and the echocardiographic features usually seen at the end of the phase of the cardiac cycle. The mitral ring has the shape of a hyperbolic paraboloid, and this peculiar geometry explains why the "apical-four chambers" view, which explores the most superficial ring segments, is the more appropriate view for detecting mitral valve prolapses. In that incidence the valvar diameter is longer (2.43 +/- 0.45 cm) that in the "parasternal view" (1.99 +/- 0.45 cm) and the angle made by the leaflets is comparatively less acute ("four chambers" = 127.41 +/- 16.45 degrees; "parasternal" = 102.05 +/- 0.17 degrees). In the "four chamber" view the point of coaptation (which represents the vertex of the referred angle) is 0.45 +/- 0.17 cm far from the echographic line usually taken as the valvar plane (EVPL-echocardiographic valvar plane line) whereas in the other view, it is more distant from this line (0.59 +/- 0.16 cm). These two last factors make both leaflets closer to the left atrium and explains why mitral valve prolapse, when present, is more easily seen in that incidence.(ABSTRACT TRUNCATED AT 250 WORDS)