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Document Details : Title: Beat-to-beat modulation of right and left ventricular positive dP/dt by afterload Subtitle: Implications for the evaluation of inotropy Author(s): CORREIA-PINTO, Jorge , LEITE-MOREIRA, Adelino F. , HENRIQUES-COELHO, Tiago , MAGELHAES, Sónia , GILLEBERT, Thierry C. Journal: Acta Cardiologica Volume: 58 Issue: 4 Date: August 2003 Pages: 327-334 DOI: 10.2143/AC.58.4.2005290 Abstract : Objectives— The rate of pressure rise (dP/dtmax) has mainly been studied in the left ventricle (LV), where it was demonstrated to be highly dependent of preload, but independent of afterload. Load dependence of right ventricular (RV) dP/dtmax is assumed to be similar to (LV)dP/dtmax, although this issue has not yet been investigated in detail.In the current study,we evaluated acute afterload dependence of dP/dtmax in both ventricles in rats. Methods and results— Adult Wistar rats (n = 8) were instrumented to record RV and LV pressures and septal-free wall diameters. RV and LV afterload elevations were performed by beat-to-beat graded constrictions of the pulmonary trunk or aortic root, respectively. Control cycles and low, moderate and high (isovolumetric) afterload levels were analysed. In both ventricles, afterload modulation of dP/dt was assessed by dP/dtmax normalized for end-diastolic dimensions (dP/dtmax/EDD) and by peak and mean accelerations of pressure rise. RV afterload elevation increased dP/dtmax, dP/dtmax/EDD, peak and mean acceleration of RV pressure rise,without changing the time from enddiastole to dP/dtmax. LV afterload elevations did not significantly change the corresponding left-sided parameters. Conclusions— In this study we demonstrated that,in contrast to the left ventricle, right ventricular dP/dtmax and dP/dtmax/EDD relation are significantly afterload sensitive. This should be taken into account for its application in the haemodynamic evaluation of cardiac function in experimental and clinical settings. |
