title: Temporal evaluation of left ventricular remodeling and function in rats with chronic volume overload.
abstract: The left ventricle (LV) significantly dilates and hypertrophies in response to chronic volume overload. However, the temporal responses in LV mass, volume, and systolic/diastolic function secondary to chronic volume overload induced by an infrarenal arteriovenous (A-V) fistula in rats have not been well characterized. To this end, LV end-diastolic pressure, size, and function (i.e., isovolumetric pressure-volume relationships in the blood-perfused isolated heart) were assessed at 1, 2, 3, 5, and 8 wk post-A-V fistula and compared with age-matched control animals. Progressive hypertrophy (192% at 8 wk), ventricular dilatation (172% at 8 wk), and a decrease in ventricular stiffness (257% at 8 wk) occurred in the fistula groups. LV end-diastolic pressure increased from a control value of 4.2 +/- 3.1 mmHg to a peak value of 15.7 +/- 3.6 mmHg after 3 wk of volume overload. A subsequent decline in LVEDP to 11.0 +/- 6.0 mmHg together with further LV dilation (169%) corresponded to a significant decrease in LV stiffness (222%) at 5 wk post-A-V fistula. Myocardial contractility, as assessed by the isovolumetric pressure-volume relationship, was significantly reduced in all A-V fistula groups; however, the compensatory remodeling induced by 8 wk of chronic biventricular volume overload tended to preserve systolic function.
authors.affiliation: Department of Physiology and Pharmacology, Auburn University, Alabama 36849-5517, USA.
authors.forename: G L
authors.initials: GL
authors.lastname: Brower
authors.forename: J R
authors.initials: JR
authors.lastname: Henegar
authors.forename: J S
authors.initials: JS
authors.lastname: Janicki
mesh_terms: D000818:Animals; D001012:Aorta, Abdominal / Q000601:surgery; D001166:Arteriovenous Shunt, Surgical; D002908:Chronic Disease; D003971:Diastole; D006940:Hyperemia / Q000503:physiopathology*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D013599:Systole; D013997:Time Factors; D014684:Venae Cavae / Q000601:surgery; D016277:Ventricular Function, Left