To examine Right Ventricle (RV) size as a predicting factor of pressure volume loop (PV loop) measurement, we assessed PV loop functional dependence on end-diastolic volume (EDV) from twenty animal and human RV datasets [1]. Methods PV loop sequences were processed to compute end-systolic elastance (Ees), ejecting pressure-volume-area (PVA), isovolumic mode pressure-volume-area (PVAiso), and isovolumic mode peak developed pressure (Piso). The outcomes of Ees, Piso, PVA, and PVAiso were then applied as dependent variables of EDV predicted trends with linear and power regression model fitting. Results Over the EDV range from 25 mL to 150 mL, the PVA and PVAiso measures were positively correlated to EDV. The Ees elastance measures were inversely EDV correlated, and Piso pressures were uncorrelated to EDV. Results of regression shown in the table, indicate PVA (R2 =.74) and PVAiso (R2 =.74) measures of contractile mechanism energy output were the optimally fitted indices by EDV prediction. Conclusions Decreasing RV elastance with increasing EDV size, may reflect a structural adaptation of larger chambers to a more extensive pulmonary vascular network. Positively correlated trends of PVA and PVAiso to the RV size, also suggest these measures form a promising basis to interpret ranges of normal function during different stages of pediatric patient growth. [1] E .N. Marcus, A Study of Cardiac Ventricle Performance Indices Estimated with Data from Single-Beat Pressure Volume Loops, Sensors & Transducers, Vol. 244, Issue 5, September 2020, pp. 1-6.