Effect of respiratory suspension on the computation of volume-based early peak filling rate to late peak filling rate ratio

Background In the intact circulation, changes in intrathoracic pressure and/or lung volume will simultaneously induce alterations in cardiac volumes, output, and contractility among other alterations [1]. In this study, we evaluate the impact of respiratory suspension on the computation of volume-based early peak filling rate (EPFR) to late peak filling rate (LPFR) ratio using peak velocitybased Doppler echo measured early peak velocity (E) to peak velocity during atrial contraction (A) measured at the tip of the mitral leaflets as the reference.