Please click here to obtain permission to reproduce this image.
Click on image to view larger version.

Figure 5 Aortic Impedance at Age 20 and 80 Years
Ascending aortic impedance shown schematically in a young 20-year-old and in an 80-year-old human subject showing the effect of doubling of characteristic impedance (older curve set higher) and early return of wave reflection (first minimum at double the frequency). In consequence of both, impedance modulus at heart rate frequency is increased 4-fold (4).