Table 2.

Changes in cardiac function under dobutamine stress assessed by MRI

Variable	Change under dobutamine stress (%)
	Control (n = 6)	m-V59M (n = 5)
Heart rate	8 ± 2*	6 ± 4*
Ejection fraction	12 ± 3***	15 ± 2***
End diastolic volume	−28 ± 6**	−20 ± 5**
End systolic volume	−48 ± 9***	−52 ± 7***
Stroke volume	−14 ± 6	−1 ± 6
Cardiac output	8 ± 2*	5 ± 2*

Data are means ± SEM for 12-week-old control (n = 6) and m-V59M (n = 5) mice

Data were compared with those acquired before stress using a repeated-measures ANOVA (with genotype as a between-subject factor and dobutamine treatment as a within-subject factor)

^* p < 0.05, ^** p < 0.01 and ^*** p < 0.001 against pre-dobutamine data; there were no significant differences between control and m-V59M mice