Three-Dimensional, Right Ventricular Surface Strain Computation From Three Dimensional Echocardiographic Images From Patients With Pediatric Pulmonary Hypertension.

Abstract

Right Ventricular (RV) dysfunction is routinely assessed with echocardiographic-derived global longitudinal strain (GLS). GLS is measured from a two-dimensional echo (2DE) image and is increasingly accepted as a means for assessing RV function. However, any 2D analysis cannot visualize the asymmetrical deformation of the RV nor visualize strain over the entire RV surface. We believe 3D surface (3DS) strain, obtained from 3D echo (3DE) will better evaluate myocardial mechanics. Components of 3DS strain (longitudinal, LS; circumferential, CS; longitudinal-circumferential shear, ɣCL; principal strains PSMax and PSMin; max shear, ɣMax; and principal angle θMax) were computed from RV surface meshes obtained with 3DE from 50 children with associated PAH, 43 children with idiopathic PAH, and 50 healthy children by computing strains from a discretized displacement field. All 3DS freewall (FW) normal strain (LS, CS, PSMax, and PSMin) showed significant decline at end-systole in PH groups (p<0.0001 for all), as did FW-ɣMax (p=0.0012). FW-ɣMax also changed in disease (p<0.0001). Limits of agreement analysis suggests that 3DS LS, PSMax, and PSMin are related to GLS. 3DS strains showed significant heterogeneity over the 3D surface of the RV. Components of 3DS strain agree with existing clinical strain measures, well classify normal -vs- PAH subjects, and suggest that strains change direction on the myocardial surface due to disease. This last finding is similar to that of myocardial fiber realignment in disease, but further work is needed to establish true associations.