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Background: Global right ventricular (RV) function is determined by the interplay of different motion components related to the myofiber architecture, and the relative importance of these components is still not thoroughly characterized. The aims of this study were to quantify the relative contributions of longitudinal, radial, and anteroposterior motion components to global RV function and to examine their determining factors in a large cohort of healthy volunteers using three-dimensional echocardiography., Methods: Three hundred healthy adults with a balanced age range and an equal sex distribution were investigated at two centers. A three-dimensional mesh model of the right ventricle was generated, and its motion was decomposed along the three anatomically relevant axes. Multiplicative relative contributions were measured by dividing the ejection fraction (EF) values generated by shortening in the longitudinal, radial, and anteroposterior directions by global RV EF (longitudinal EF index [LEFi], radial EF index [REFi], and anteroposterior EF index, respectively). The circumferential contribution was defined as shortening in the radial and anteroposterior directions, omitting only longitudinal shortening., Results: Circumferential EF index was markedly higher compared with LEFi (79 ± 7% vs 47 ± 9%, P < .001). LEFi (47 ± 9%) and anteroposterior EF index (49 ± 7%) were found to be similar in the pooled population, whereas REFi (44 ± 10%) was lower (P < .001). In younger individuals (20-39 years of age), the relative contribution of longitudinal shortening was significantly higher compared with the radial component; however, in the older age groups, LEFi and REFi were comparable. Age, body surface area, heart rate, and RV end-diastolic volume were independent predictors of LEFi and REFi, but all with opposite effects on the two motion directions., Conclusions: In contrast to the traditional viewpoint, the contributions of the radial and anteroposterior motion directions may be of comparable significance with that of longitudinal shortening in determining global RV function. Standard parameters referring only to longitudinal shortening of the right ventricle may be inadequate to characterize RV function thoroughly., (Copyright © 2020 American Society of Echocardiography. Published by Elsevier Inc. All rights reserved.)

Background: Right ventricular (RV) dysfunction has been associated with poor prognosis in chronic heart failure (HF). However, less data is available about the role of RV dysfunction in patients with cardiac resynchronization therapy (CRT). We aimed to investigate if RV dysfunction would predict outcome in CRT., Design: We enrolled prospectively ninety-three consecutive HF patients in this single center observational study. All patients underwent clinical evaluation and echocardiography before CRT and 6 months after implantation. We assessed RV geometry and function by using speckle tracking imaging and calculated strain parameters. We performed multivariable Cox regression models to test mortality at 6 months and at 24 months., Results: RV dysfunction, characterized by decreased RVGLS (RV global longitudinal strain) [10.2 (7.0-12.8) vs. 19.5 (15.0-23.9) %, p<0.0001] and RVFWS (RV free wall strain) [15.6 (10.0-19.3) vs. 17.4 (10.5-22.2) %, p = 0.04], improved 6 months after CRT implantation. Increasing baseline RVGLS and RVFWS predicted survival independent of other parameters at 6 months [hazard ratio (HR) = 0.37 (0.15-0.90), p = 0.02 and HR = 0.42 (0.19-0.89), p = 0.02; per 1 standard deviation increase, respectively]. RVGLS proved to be a significant independent predictor of mortality at 24 months [HR = 0.53 (0.32-0.86), p = 0.01], and RVFWS showed a strong tendency [HR = 0.64 (0.40-1.00), p = 0.05]. The 24-month survival was significantly impaired in patients with RVGLS below 10.04% before CRT implantation [area under the curve = 0.72 (0.60-0.84), p = 0.002, log-rank p = 0.0008; HR = 5.23 (1.76-15.48), p = 0.003]., Conclusions: Our findings indicate that baseline RV dysfunction is associated with poor short-term and long-term prognosis after CRT implantation.