RESUMO
OBJECTIVE: To determine the systolic parietal stress of the left ventricle by image of magnetic resonance in healthy subjects. MATERIAL AND METHODS: 21 healthy subjects studied: 11 male and 10 female: the ages among 26 and 31 years (29.33). A magnetic resonance of heart was made using the short axis at the level of the papillary muscles, from where the epicardic and endocardic areas of the left ventricular cavity were obtained in diastolic as in systolic by means of the layout with an electronic pencil, later the radius of each drawn up area was calculated, with the value of the radius, the diastolic and systolic thickness was calculated; to obtain the relation between thickness/radio. Once the relation was obtained between thickness/radio in diastole as systole the degree of change between both values and the percentage of this change was calculated. Finally, the systolic parietal stress developed by the left ventricle was calculate with the following formula: S = PVI x A4/A3-A4 x 1.35.PVI: systolic pressure of the left ventricle (the average of 5 synchronized systolic arterial pressures, obtained by an esphingomanometer). A4: endocardic area in systole; A3: epicardial area in systole. The value obtained in this equation was multiplied per 1.35 to turn mmHg gm/cm2. RESULTS: The average of the arterial systolic pressure was of 103.24 +/- 10.27 mmHg; A3 (average 27.58 +/- 2.29); A4 (average 6.84 +/- 0.71); being the systolic stress of the left ventricle of 46.12 +/- 4.9 gm/cm2, not existing significant differences between sexes. CONCLUSIONS: With this new method it is possible to determine with greater exactitude in a noninvasive way, through the best definition of its epicardic and endocardic edges, the areas and the radio of the left ventricular cavity in systole as in diastole, to determine the thickness of the wall and its relation with the radius, for one better valuation of the ventricular function, specially in those subjects with overloads of volume or pressure that depress the ventricular function.
Assuntos
Imageamento por Ressonância Magnética , Sístole , Função Ventricular Esquerda , Adulto , Fenômenos Biofísicos , Biofísica , Feminino , Humanos , Masculino , Estresse MecânicoRESUMO
Objetivo: Determinar el estrés meridional parietal sistólico del ventrículo izquierdo por imagen de resonancia magnética en sujetos sanos. Material y métodos: Se estudiaron 21 sujetos sanos: 11 pertenecían al sexo masculino y 10 al femenino: su edad varió entre 26 y 31 años (29.33). Se les realizó el estudio de resonancia magnética de corazón utilizando el eje corto a nivel de los músculos papilares, de donde se obtuvieron las áreas epicárdicas y endocárdicas de la cavidad ventricular izquierda tanto en diastole como en sístole mediante el trazado con un lápiz electrónico, posteriormente se calculó el radio de cada área trazada, con el valor del radio, se calculó el espesor diastólico y sistólico; para posteriormente obtener la relación grosor/radio. Ya obtenida la relación grosor/radio tanto en diastole como sístole se calculó el grado de cambio entre ambos valores y el porcentaje de dicho cambio. Finalmente se calculó el estrés meridional parietal sistólico desarrollado por el ventrículo izquierdo mediante la siguiente fórmula: S=PVI x A4/A3-A4 x 1.35. PVI: presión sistólica del ventrículo izquierdo (promedio de 5 tomas simultáneas de presión arterial sistólica, obtenidas mediante esfingomanómetro). A4: área endocárdica en sístole; A3: área epicárdica en sístole. El valor obtenido en esta ecuación se multiplicó por 1.35 para convertir mmHg en gm/cm². Resultados: La presión arterial sistólica media fue de 103.24 ± 10.27 mmHg; A3 (media 27.58 ± 2.29); A4 (media 6.84 ± 0.71); siendo el estrés meridional sistólico del ventrículo izquierdo de 46.12 ± 4.9 gm/cm², no existiendo diferencias significativas en cuanto al sexo. Conclusiones: Con este nuevo método es posible determinar con mayor exactitud de manera no invasiva, a través de la mejor definición de sus bordes epicárdicos y endocárdicos, las áreas y los radios de la cavidad ventricular izquierda tanto en sístole como en diastole, determinar el grosor de la pared y su relación con el radio, esto para una mejor valoración de la función ventricular, en especial en los sujetos con sobrecargas de presión o de volumen que deprimen la función ventricular.
Objective: To determine the systolic parietal stress of the left ventricle by image of magnetic resonance in healthy subjects. Material and methods: 21 healthy subjects studied: 11 male and 10 female: the ages among 26 and 31 years (29.33). A magnetic resonance of heart was made using the short axis at the level of the papillary muscles, from where the epicardio and endocardio areas of the left ventricular cavity were obtained in diastolic as in systolic by means of the layout with an electronic pencil, later the radius of each drawn up area was calculated, with the value of the radius, the diastolic and systolic thickness was calculated; to obtain the relation between thickness/radio. Once the relation was obtained between thickness/radio in diastole as systole the degree of change between both values and the percentage of this change was calculated. Finally, the systolic parietal stress developed by the left ventricle was calculate with the following formula: S=PVI x A4/A3-A4 x 1.35.PVI: systolic pressure of the left ventricle (the average of 5 synchronized systolic arterial pressures, obtained by an esphingomanometer). A4: endocardio area in systole; A3: epicardial area in systole. The value obtained in this equation was multiplied per 1.35 to turn mmHg gm/cm². Results: The average of the arterial systolic pressure was of 103.24 ± 10.27 mmHg; A3 (average 27.58 ± 2.29); A4 (average 6.84 ± 0.71); being the systolic stress of the left ventricle of 46.12 ± 4.9 gm/cm², not existing significant differences between sexes. Conclusions: With this new method it is possible to determine with greater exactitude in a noninvasive way, through the best definition of its epicardio and endocardic edges, the areas and the radio of the left ventricular cavity in systole as in diastole, to determine the thickness of the wall and its relation with the radius, for one better valuation of the ventricular function, specially in those subjects with overloads of volume or pressure that depress the ventricular function.