Figure 200k

The sound and pressure correlates of S2 in a seventeen year old patient with normal pulmonary artery pressure (left panel) are contrasted with the sound and pressure correlates of two patients with severe pulmonary hypertension.
The center panel shows narrow splitting of S2 on the external phonocardiogram, while in the right panel there is wide splitting of
S2. There is a marked reduction in the hangout interval in both patients
with severe pulmonary hypertension compared to the patient with normal pulmonary artery pressure. In the center panel, the duration of the left and right ventricular systole is nearly equal, and narrow spitting of S2 results.
In the right panel, significant prolongation of right ventricular mechanical systole beyond left ventricular systole delays P2 producing wide splitting of S2.