Strain generation and right ventricular systolic function: The sum of all its parts

BACKGROUND: Speckle-tracking echocardiography (STE) has provided a reliable means to enhance characterization and quantification of global right ventricular (RV) systolic function. The use of Automated Functional Imaging (AFI) software has been previously used to quantify RV longitudinal peak global strain (PGS) values during two-dimensional (2D) transthoracic echocardiographic examinations. However, there is a paucity of data regarding relative strain contribution of each individual regional segments when compared with global strain assessment. Consequently, our goal was to use AFI STE to examine the strain contribution of each regional segment when assessing RV function. METHODS: A retrospective analysis was performed on 107 patients that met our study criteria to correlate 2D TTE measures of RV systolic function to both RV AFI STE longitudinal peak global strain (PGS) and each individual regional RV free wall (RVFw) and inter-ventricular septum (IS) strain values. RESULTS: We found that TTE variables of RV systolic function only correlated with PGS (RVFAC; P < .0001, TAPSE; P < .0001, and TA TDI S'; P < .0001) but none of the six individual regional AFI strain values. When PGS was not included in the multivariate analysis, only the mid RVFw and mid IS strain regions correlated with measures of RV systolic function. CONCLUSIONS: Regional differences do exist with regards to strain generation along the RVFw and IS. These differences could be physiologically and anatomically explained based on our current understanding of RV muscle fiber arrangement. Further research is now needed to better characterize RV function in different clinical entities.