The in vivo quantification of myocardial performance in rabbits: a model for evaluation of cardiac gene therapy. J Mol Cell Cardiol 1996 May;28(5):815-23
Date
05/01/1996Pubmed ID
8762021DOI
10.1006/jmcc.1996.0076Scopus ID
2-s2.0-0029996935 (requires institutional sign-in at Scopus site) 15 CitationsAbstract
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.
Author List
Silvestry SC, Taylor DA, Lilly RE, Atkins BZ, Marathe US, Davis JW, Kraus W, Glower DDMESH terms used to index this publication - Major topics in bold
AnimalsGenetic Therapy
Heart
Heart Diseases
Rabbits