Fig. 9. Cardiac performance in isolated hearts (N=4) in vitro as
a function of temperature. (A) Examples of blood flow in sternal artery
measured at the indicated temperatures. (B) Heart rate (mean ± s.d.)
measured as a function of temperature. (C) Stroke volume (mean ± s.d.)
measured as a function of temperature. The data show a linear trend with an
estimated slope of –0.070 (s.e.m.=0.017, P<0.001). (D)
Cardiac output (mean ± s.d.), measured as a function of temperature, is
represented by the symbols and solid lines. The broken line represents the
estimated means based on the quadratic equation as follows: mean cardiac
output=19.18(±5.4)+5.01(±0.91)x
(temperature)–0.25(±0.04)x(temperature)2, where
values in parentheses are standard errors. The estimated maximum for the
fitted curve is at temperature=9.90, 95% confidence interval (3.6, 16.2).
*Data are significantly different from values at 2°C
(P<0.05).