Tone Iv

Tone IV is the fourth systolic sound that appears during the expulsion of blood from the left ventricle into the atria. It is a powerful shock tone, accompanied by rapid and noisy filling of the ventricles.

The following characteristics of tone IV are distinguished: - Measured and directional sound. - Heard over the entire heart area.

Heart sound IV appears when performing an orthotest, after which it gradually decreases and disappears when sound II appears. With valve insufficiency, tone I disappears already at the beginning of diastole. It appears when pressure increases. The intensity and pitch of tone IV depend on the phase of the cardiac cycle, and in women the volume is many times lower against the background of increased estradiol content.