Determination of Cardiac Output by Doppler Echocardiography inApparently Healthy, Non-Athletic Men Aged 20-70 Years

In order to obtain reference values related to age, the cardiac output (CO) was measured by pulsed Doppler in 92 apparently healthy, non-obese, non-athletic men aged 21-69 (mean 43) years with an Irex Meridian system. The aortic flow was recorded from the apical window with the sampling volume in the left ventricular outflow tract. The integral of maximum velocity was calculated by planimetry. The aortic diameter was taken as the distance between insertion of anterior and posterior cusps on the cross-sectional echocardiogram using the leading edge principle. The mean (± 1 SD) CO was 5.46 ± 1.12 litres/min and the cardiac index 2.81 ± 0.57 litres/min/m2. No significant age-related correlations were observed for heart rate, integral of maximum velocity, stroke volume, CO, or cardiac index, whereas the aortic diameter showed a weak positive correlation with age (r = 0.21 ; p < 0.05). In the subgroup aged 30-70 years, significant positive correlations between age and aortic diameter (r = 0.43; p < 0.001), stroke volume (r = 0.28; p < 0.01), and CO (r = 0.21; p < 0.05) were noted. In 7 male patients with coronary heart disease evaluated by right-sided heart catheterization prior to peripheral artery surgery, CO measured by Doppler correlated well with CO obtained by thermodilution (r = 0.90; p < 0.001).