Left Ventricular Geometry and Near-Simultaneous Invasive Hemodynamics in Pediatric Pulmonary Hypertension

ransthoracic echocardiography (TTE) in children usually allows a comprehensive assessment of the cardiovascular anatomy. 6] To date, VVI variables such as the LV endsystolic eccentricity index (LVes-EI) is not commonly assessed in patients with pediatric PH in clinical practice. The physiology of VVI is based on the pericardium, movement of the interventricular septum, and myocardial tracts running between the ventricles. The impact of the RV under pressure is related to underfilling and dysfunction of the compressed LV, which reduces LV output. As RV pressure load progresses, the enhanced VVI leads to impaired LV filling. In RV systole, the LV cavity is compressed owing to leftward bowing of the ventricular septum, causing a reduction in LV preload, and low LV output. The RV/LV end-systolic dimension ratio, taken in the parasternal shortaxis view, was derived to combine a measure of RV size with septal shift secondary to elevated RV pressure. The VVI variables LVesEI and RV/LV end-systolic dimension ratio are associated with lower functional class, worse hemodynamics, and higher NT-proBNP levels, 11 thus highlighting the importance of VVI in pediatric PH. In a recent study, we found the LVesEI to positively correlate with an RV end-systolic remodeling index, indicating that RV deformation acts in combination with RV/LV interaction. n this issue of Circulation: Cardiovascular Imaging, Burkett et al 13 evaluated LV shape measures in children and young adults with PH. TTE was performed near-simultaneously with cardiac catheterization, allowing-for the first time-a direct comparison between invasive hemodynamics and measures of LV shape. The authors present a new TTE measure, entitled the maximal eccentricity index (EIM). This measure is essentially the LVesEI and highlights the role of substantial, indeed post-systolic maximal septal flattening that is frequently found in PH. Most of the 78 patients with PH were on at least one PAH-targeted medication (92%), and all patients had systemic saturations >90%, 13 indicating either no significant or predominant left-to-right