Cué Carpio José Ramón, Meave Aloha, Guadalajara Boo José Fernando
Instituto Nacional de Cardiologia "Ignacio Chávez" (INCICH, Juan Badiano No. 1 Col. Sección XVI, Tlalpan 14080, México, DF.
Arch Cardiol Mex. 2005 Jan-Mar;75(1):61-70.
To determine the systolic parietal stress of the left ventricle by image of magnetic resonance in healthy subjects.
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.
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.
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.
通过磁共振成像测定健康受试者左心室的收缩期壁应力。
研究21名健康受试者，其中11名男性和10名女性，年龄在26至31岁之间（平均29.33岁）。使用乳头肌水平的短轴进行心脏磁共振成像，通过电子笔布局在舒张期和收缩期获取左心室腔的心外膜和心内膜面积，随后计算每个绘制区域的半径，利用半径值计算舒张期和收缩期厚度；得出厚度/半径的关系。在得出舒张期和收缩期厚度/半径的关系后，计算两者之间的变化程度及其变化百分比。最后，用以下公式计算左心室产生的收缩期壁应力：S = PVI×A4/A3 - A4×1.35。PVI：左心室收缩压（通过血压计获得的5次同步收缩期动脉压的平均值）。A4：收缩期的心内膜面积；A3：收缩期的心外膜面积。该方程所得值乘以1.35换算为mmHg gm/cm²。
动脉收缩压平均值为103.24±10.27 mmHg；A3（平均值27.58±2.29）；A4（平均值6.84±0.71）；左心室收缩期应力为46.12±4.9 gm/cm²，性别之间无显著差异。
通过这种新方法，能够以更高的精确度无创地确定收缩期和舒张期左心室腔的心外膜和心内膜边缘、面积及半径，确定室壁厚度及其与半径的关系，以便更好地评估心室功能，特别是对于那些存在容量或压力超负荷且使心室功能降低的受试者。
