The contraction and relaxation of the heart are equivalent to the periodic vibration of the object relative to the medium. The ventricular wall velocity measured by static instrument is V, which is based on the Doppler effect formula.

f'=fc/(c v)

δf = | f '-f | = f(v/c)

Where c =1500m/s, f = 5000kh and δ f = 0.5h..

Solve v = c * [(δ f/f) 1]

Note that (δ f/f = 10000, so [(δ f/f) 1] is about 10000.

Substituting the solution, the heart rate v = 0.15m/s.