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Echocardiographic assessment of the inferior vena cava wall motion for studies of right heart dynamics and function
Abstract:
Using subcostal echocardiography, 97 patients with diseases involving the right side of the heart and 15 normal subjects were examined in order to study the inferior vena cava (IVC) wall motion. All cases had a diagnostic cardiac catheterization and routine echocardiogram. The jugular pulse (JP) was recorded in 35 random cases contemporary to the IVC and tricuspid valve (TV) tracings. The aim of the study was to evaluate the variations of the IVC diameters in different cardiopathies and in relation to the right atrial mean pressure and the time-relationship of the IVC wall motion related to the cardiac rhythm and cycle, respiratory events, and JP and TV waves. The a, b, v, and y waves were identified on the IVC tracings and related to the respective waves of the JP and the points of closure and opening of the TV. The IVC a and v waves were coincident with the TV closure and opening, and therefore, considered as moments of maximal presystolic and systolic filling of the IVC. The JP a wave inscribed before, whereas the v wave did so after the same IVC waves, respectively. The IVC a wave was due to the atrial contraction and influenced by the cardiac rhythm. The emptying index (EI) was calculated from the diameters in a and b as a - b/a X %, whereas the collapsability index (CI) was calculated from the expiratory and inspiratory diameters as Ex - In/Ex X %, obtaining a good correlation with the right atrial mean pressure. Finally, the percentage systolic pulsation (SP) was calculated from the diameters in b and v as b - v/b X %. The indices of function of the IVC have been very useful in the evaluation of patients with raised heart pressure, tricuspid regurgitation, and pericardial effusion. From the present investigation it results that the IVC wall motion, more so than the JP waves, is an expression of right atrial and ventricular events, and that the above indices are an expression of the atrial and ventricular function in relation to the hemodynamic situation.