Echocardiographic evaluation of cardiac function in cynomolgus monkeys over a wide age range

Figures

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  Fig. 1.. Chest x-rays and electrocardiograms (ECGs) indicate no abnormal findings. In this study, we applied screening tests such as chest X-ray (A) and ECG (B) for all monkeys. This x-ray suggests that the monkey has no cardiac or pulmonary dysfunction (A). This ECG, which is enhanced to double the amplitude of each wave, shows no cardiac load or electrophysiological abnormalities (B). Similar x-ray and ECG results were seen for all monkeys.

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  Fig. 2.. Changes in cardiac structures including LA and AO diameter with age and weight. Graph shows cardiac structures related to LA and AO. Results of ANOVA (A–C). LAD remains essentially stable at all ages, with a slight tendency toward an increase in the mature group compared immature group (A). AOD and LA/AO ratio increased in all aging stages (B, C). Especially, aortic diameter at dilation increased remarkably with aging and growth (B) and LA/AO ratio concomitantly decreased (C). Diameter of LV walls (C, D). IVSd and LVPW increased until reaching maturity and then stabilized (D–F). Statistical outliers are plotted outside of the error bar. *P<0.05, **P<0.01, ***P<0.001; one-way ANOVA and Tukey’s test.

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  Fig. 3.. Age-related changes in LV systolic function. This graph shows the relationship between LV function and aging. The X-axis range of coefficient lines indicates the 95%CI. Left ventricular systolic function was not obviously affected by aging, whereas SV (A), CO (B), EF (C) and FS (D) slightly increased with age. SV increases with aging and CO remains stable at all ages in humans, whereas our data show that SV and CO constantly increased with aging. Findings of EF and FS were similar to those in humans.

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  Fig. 4.. Inflow and outflow velocity according to age and body weight. This graph shows the relationships of in- or outflow velocity and aging. The x-axis range of coefficient lines indicates the 95%CI. Flow was stable in TV (A), slightly increased in PA (B), and somewhat decreased in AV with age (C). Like LV systolic functions, inflow and outflow velocity of cardiac valves were stable and not affected by aging due to various buffer mechanisms. E waves apparently decreased with aging (D), and E/A ratio showed the same tendency (F) due to the influence of changes in E waves. In contrast, A waves remained stable at all ages (E). E and A waves also decreased as body weight increased (G, H), but E/A ratio clearly decreased with age (I). These findings showed that atrial systolic function compensates for LV diastole function, and suggest that E waves consequently decrease.