This is an example of mild pulmonic regurgitation which can be caused by an infection of the pulmonic valve leaflets.
The first and second heart sounds are normal (S2 is split).
Systole is silent.
A high pitched decrescendo murmur occupying the first half of diastole can be heard starting immediately after the second heart sound.
The murmur is best heard at the pulmonic area and can be accentuated by having the patient sitting up and leaning forward.
The intensity of the murmur increases with inspiration, indicating the right-sided origin of the murmur.
In the animation you can see the turbulent blood flow from the pulmonary artery into the right ventricle during early diastole. You can see the minimally thickened pulmonic valve leaflets.