These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Effects of reduced resistive afterload on left ventricular pressure-volume relationship.
    Author: Ducas J, Schick U, Girling L, Prewitt RM.
    Journal: Am J Physiol; 1985 Feb; 248(2 Pt 2):H163-9. PubMed ID: 3970220.
    Abstract:
    In seven anesthetized, beta-blocked dogs, we investigated the effects of a reduction in systemic vascular resistance (SVR) on left ventricular (LV) systolic mechanics. LV pressure and volumes (scintigraphic techniques) were measured in base-line condition, after opening one and then two arteriovenous fistulas (AVF). Volume was infused to maintain LV end-systolic pressure (LVESP). Despite a constant ESP, the mean end-systolic volume (LVESV) fell from 42 to 31 ml (P less than 0.025) when the SVR fell from 81 to 48 units (P less than 0.0025), and the LVESV fell further to 24 ml (P less than 0.0025) when the SVR was decreased to 30 units (P less than 0.025). In six similarly prepared dogs, aortic flow was measured, and when resistive afterload decreased, instantaneous flow increased. Since end-diastolic volume was not significantly changed when resistive afterload decreased, instantaneous LV volume decreased despite constant systolic LV pressure. In two of these dogs, LV pressure-volume (PV) trajectories were drawn for the ejection period. When SVR decreased there was a marked leftward shift of the PV trajectory as the end of ejection was approached. It is concluded that at a given contractile state and ventricular pressure, alterations in resistive load directly affect rate and extent of ventricular shortening.
    [Abstract] [Full Text] [Related] [New Search]