Non-invasive indices of cardiac systolic and diastolic function in
the hyperthyroid and senescent mouse.
Taffet, George E., Craig J. Hartley, Xiouying Wen, Thuy Pham, Lloyd H.
Michael, and Mark L. Entman.
Sections of Cardiovascular Sciences and Geriatrics, Department of
Medicine, Baylor College of Medicine, Houston, Texas 77030
APStracts 2:0523H, 1995.
The mouse is a common model for transgenic manipulation, however,
their small size has made hemodynamic study difficult. A noninvasive
10 MHz pulsed Doppler probe was used to measure aortic and mitral
flow velocities in anesthetized, intact mice to study the effects of
aging and hyperthyroidism (induced by thyroxine) on systolic and
diastolic cardiac function. In 10 hyperthyroid mice peak aortic
velocity (PAV, an index of systolic function) was 34% higher than in
10 control mice (108+2 vs 80+3 cm/s, p<0.05). The ratio of early
to late mitral filling velocity (E/A ratio, an index of diastolic
function) was 47% higher (5.6+0.8 vs. 3.8+0.2, p<0.05) in the
hyperthyroid mice. In 6 old (30 months) mice PAV was similar to 8
young (4 month) mice (73+3 vs. 75+3 cm/s), but the E/A ratio was 59%
lower (1.8+0.3 vs. 4.4+0.4, p<0.05). Despite a wide range of
observed heart rates, the systolic and diastolic parameters of the
groups were clearly separated. We conclude that cardiac systolic and
diastolic function in mice, measured by pulsed Doppler ultrasound,
are similar to larger species both in magnitude and in their response
to hyperthyroidism and aging.
Received 6 July 1995; accepted in final form 10 November 1995.
APS Manuscript Number H619-5.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 8 December 95