Table 2.

Echocardiographic measurements in young and aged CHT^+/+ and CHT^+/− mice

	Young Mice		Aged Mice
Parameter	CHT+/+	CHT+/−	CHT+/+	CHT+/−
No. of mice/group	8	9	8	8
LV internal dimension at diastole, mm	0.292 ± 0.005	0.330 ± 0.006*	0.342 ± 0.008	0.333 ± 0.009
LV internal dimension at systole, mm	0.149 ± 0.004	0.191 ± 0.006*	0.186 ± 0.008	0.198 ± 0.002
Cardiac output, ml/min	15.36 ± 0.7310	19.59 ± 1.221	23.86 ± 1.08	20.66 ± 1.38†
Stroke volume, ml	0.021 ± 0.001	0.029 ± 0.001*	0.031 ± 0.002	0.029 ± 0.002
HR (beats/min)	704.5 ± 5.61	675.8 ± 16.59	692.2 ± 7.4	705 ± 7.55
Fractional shortening, %	48.83 ± 0.667	41.89 ± 0.9484*‡	44.29 ± 1.16	39.26 ± 0.853†‡
LV mass, g	0.065 ± 0.004	0.075 ± 0.004	0.079 ± 0.006	0.098 ± 0.004†

Values are means ± SE. LV, left ventricular. Significance was determined using a one-tailed, unpaired Student's t-test.

^*P < 0.05 in young CHT^+/− vs. CHT^+/+ mice;

^†P < 0.05 in aged CHT^+/− vs. CHT^+/+ mice;

^‡P < 0.05 in young vs. aged CHT^+/− mice.