Age-related left ventricular function in the mouse: analysis based on in vivo pressure-volume relationships.
Our study compared left ventricular (LV) function between senescent and young adult mice through in situ pressure-volume loop analysis. Two groups of mice (n = 9 each), 6-mo-old and 16-mo-old (senescent) mice, were anesthetized with urethan and alpha-chloralose, and their LV were instrumented with a Millar 1.4-Fr conductance micromanometer catheter for the acquisition of the pressure-volume loops. The senescent mice had a significantly decreased contractile function related to load-dependent parameters, including stroke volume index, ejection fraction, cardiac output index, stroke work index, and maximum derivative of change in systolic pressure over time. The load-independent parameters, preload recruitable stroke work and the slope (end-systolic volume elastance) of the end-systolic pressure-volume relationship, were significantly decreased in the senescent mice. Heart rate and arterial elastance were not different between the two groups; however, the ventricular-to-vascular coupling ratio (ratio of elastance of artery to end-systolic volume elastance) was increased by threefold in the senescent mice (P < 0. 001). Thus there were significant decreases in contractile function in the senescent mouse heart that appeared to be related to reduced mechanical efficiency but not related to arterial elastance.
Yang
B
B
Arizona Prevention Center, University of Arizona, Tucson, Arizona 85724, USA.
Larson
D F
DF
Watson
R
R
D000375:Aging / Q000502:physiology*; D000818:Animals; D001794:Blood Pressure / Q000502:physiology; D001810:Blood Volume / Q000502:physiology; D005260:Female; D006439:Hemodynamics; D051379:Mice; D008810:Mice, Inbred C57BL; D009200:Myocardial Contraction; D016277:Ventricular Function, Left / Q000502:physiology*