AFTERLOAD SENSITIVITY OF NONLINEAR END-SYSTOLIC PRESSURE-VOLUME RELATION VS PRELOAD RECRUITABLE STROKE WORK IN CONSCIOUS DOGS

The observations in vivo of a non-linear, afterload-sensitive end-syst olic pressure-volume relation (ESPVR) and a linear, load-insensitive p reload recruitable stroke work (PRSW) relation may be reconciled by co nsidering the PRSW as a product of both the ventricular ESPVR and the arterial elastance (E-a). We obtained pressure-volume data from eight conscious dogs. The ESPVR was nonlinear, and its trajectory was afterl oad-dependent. The PRSW was linear and load-independent. Arterial elas tance changed with both acute reductions in preload and steady-state c hanges in afterload. The PRSW relation thus describes both myocardial function and ventricular-arterial interaction and is a useful index of cardiovascular performance in patients. (C) 1998 Academic Press.