Table 1.

Summary of echocardiographic data in response to isoproterenol (ISO) by age and sex. Heart rate (HR), end systolic volume (ESV), end diastolic volume (EDV), stroke volume (SV), ejection fraction (EF), fractional shortening (FS), cardiac output (CO), and diastolic and systolic thickness of left ventricle anterior wall (LVAWd and LVAWs). LVAWs and LVAWd differed by age (pediatric < adult < geriatric). Data are presented as means ± SEM. *P < 0.05 as assessed by 3-way ANOVA and Fisher’s post hoc test to compare ISO and CON within age and sex

	Juvenile				Adult				Aged
	Male		Female		Male		Female		Male		Female
	CON (n = 4)	ISO (n = 5)	CON (n = 5)	ISO (n = 5)	CON (n = 3)	ISO (n = 4)	CON (n = 5)	ISO (n = 4)	CON (n = 4)	ISO (n = 4)	CON (n = 4)	ISO (n = 3)
HR (bpm)	515 ± 39	568 ± 38	513 ± 19	646 ± 27*	451 ± 28	652 ± 9*	462 ± 21	645 ± 26*	527 ± 38	528 ± 22	570 ± 56	615 ± 41
ESV (μL)	12.6 ± 1.1	12.0 ± 2.6	11.3 ± 0.8	9.6 ± 1	34.1 ± 3.9	6.1 ± 1.3*	9.7 ± 1.5	13.0 ± 3.9	17.8 ± 6.4	15.2 ± 3.1	8.9 ± 0.8	4.9 ± 0.8
EDV (μL)	36.2 ± 1.5	42.7 ± 7.6	39.3 ± 2.4	33.9 ± 3.2	73.6 ± 6.4	40.4 ± 3.2*	40.1 ± 2.8	48.4 ± 10.8	64.9 ± 15.4	55.9 ± 13.8	45.02 ± 7.6	38.1 ± 4.8
SV (μL)	24 ± 2	31 ± 6	28 ± 2	24 ± 3	40 ± 3	34 ± 2	30 ± 1	36 ± 7	47 ± 9	41 ± 11	36 ± 8	33 ± 4
EF (%)	65 ± 4	72 ± 4	71 ± 1	72 ± 1	54 ± 2	85 ± 2*	76 ± 2	75 ± 3	75 ± 4	72 ± 2	79 ± 3	87 ± 2
FS (%)	35 ± 3	41 ± 3	39 ± 1	51 ± 7*	28 ± 1	54 ± 2*	44 ± 2	43 ± 3	44 ± 3	41 ± 2	47 ± 4	55 ± 2
CO (mL/min)	12 ± 1	17 ± 3	15 ± 1	16 ± 1	16 ± 2	22 ± 1*	14 ± 0.4	22 ± 3*	24 ± 4	22 ± 6	20 ± 3	21 ± 3
LVAWs (mm)	1.09 ± 0.12	1.54 ± 0.08*	1.29 ± 0.1	1.54 ± 0.11	0.99 ± 0.08	1.89 ± 0.10*	1.36 ± 0.10	1.83 ± 0.14*	2.06 ± 0.23	1.81 ± 0.14	1.76 ± 0.15	1.74 ± 0.84
LVAWd (mm)	0.66 ± 0.09	0.94 ± 0.10	0.81 ± 0.05	1.05 ± 0.09	0.86 ± 0.06	1.07 ± 0.10	0.93 ± 0.09	1.12 ± 0.16	1.32 ± 0.22	1.13 ± 0.12	1.08 ± 0.19	2.13 ± 0.43