The in vivo quantification of myocardial performance in rabbits: a model for evaluation of cardiac gene therapy.

Published

Journal Article

Evaluating cardiac gene therapy in the intact animal requires an index of cardiac function capable of detecting regional differences in contractility in a load-independent fashion. Potentially load-insensitive measures of ventricular performance were therefore evaluated in 10 open- and closed-chested, anesthetized rabbits. LV transmural pressure and myocardial segment length were measured using micromanometry and sonomicrometry during steady-state and transient inferior vena caval occlusion, over a range of inotropic and loading conditions. For each intervention, segmental stroke work was calculated as the area within the left ventricular transmural pressure-length loops at a given end-diastolic segment length during inferior vena caval occlusion; regression analysis was applied to obtain the linear Frank-Starling relationship. In both open- and closed-chested states, these relationships were highly linear (r = 0.97 +/- 0.1) and reproducible. The slope of the linear relationship between segmental stroke work and end-diastolic segment length increased significantly with calcium and epinephrine infusions (P < 0.05 v control) but was not significantly altered by decreased afterload or increased afterload (P > 0.4). The x-intercept was not significantly altered by changes in intropy or afterload (P > 0.4). These data validate the linear Frank-Starling relationship and the slope, MW, as a load-insensitive index of contractility in the intact rabbit. This study presents a novel approach to the quantification of regional cardiac function in smaller animals.

Full Text

Duke Authors

Cited Authors

  • Silvestry, SC; Taylor, DA; Lilly, RE; Atkins, BZ; Marathe, US; Davis, JW; Kraus, W; Glower, DD

Published Date

  • May 1996

Published In

Volume / Issue

  • 28 / 5

Start / End Page

  • 815 - 823

PubMed ID

  • 8762021

Pubmed Central ID

  • 8762021

International Standard Serial Number (ISSN)

  • 0022-2828

Language

  • eng

Conference Location

  • England