Table 2.

Species differences in LV dimensions and function at baseline and under stress conditions

BaselineDobutamine
MouseNMRSignificanceMouseNMRSignificance
Heart rate, beats/min461 ± 14229 ± 10<0.0001600 ± 16306 ± 13<0.0001
Average diastolic wall thickness, mm0.77 ± 0.030.87 ± 0.020.01980.77 ± 0.030.88 ± 0.020.0152
LV end-diastolic dimension, mm3.67 ± 0.084.03 ± 0.24N.S.3.34 ± 0.093.74 ± 0.21N.S.
LV end-systolic dimension, mm2.27 ± 0.122.93 ± 0.240.02391.66 ± 0.082.08 ± 0.18N.S.
Fractional shortening, %39 ± 228 ± 20.000252 ± 246 ± 20.0345
Ejection fraction, %57 ± 343 ± 20.000879 ± 175 ± 2N.S.
Cardiac output, ml/min14.9 ± 0.76.5 ± 0.4<0.000121.7 ± 0.911.5 ± 1.1<0.0001
Stroke volume, μl34.4 ± 1.426.0 ± 1.40.00134.9 ± 1.337.2 ± 3.6N.S.
  • All values are means ± SE. LV, left ventricular. Sample sizes are n = 10 (5/sex) animals for each species. Significance is indicated by P values; N.S. denotes P > 0.05.