Let us begin auscultation at the upper right sternal edge using the diaphragm of the stethoscope. Everybody listen together. [Cut-away]
What we heard at the upper right sternal edge was S1 and S2, but S2 was clearly very loud. We didn't hear [sounds], we heard [sounds]. Now, why do we have a loud second heart sound? It can be due to the aortic or the pulmonary component. When you only hear one sound, you can't be sure. If it's the aortic component, think systemic arterial hypertension; if it's the pulmonary component, you think of pulmonary hypertension. And, in the context of what we know about our patient so far, pulmonary hypertension must be a consideration.
Auscultation URSE discussion
The presence of a loud single second heart sound at the upper right sternal edge may reflect enhanced closure of the aortic or pulmonary valve. An abnormally loud aortic component is commonly due to systemic hypertension; while a loud pulmonic component is typically the result of pulmonary hypertension.