Hg systolic unless the main pulmonary artery is markedly dilated. A soft Graham Steell's murmur may even decrease with inspiration despite the increase in pulmonary artery flow because the soft pulmonary regurgitation murmur is usually best heard at the 2nd left intercostal space where inspiration pushes the stethoscope away from the chest. After the release of a Valsalva strain, the pulmonary regurgitation murmur immediately resumes its loudness, whereas the aortic regurgitation murmur requires four to five beats to do so. Rheumatic AS results from fibrosis of the leaflets and fusion of the commissures. Regardless of whether AS is congenital or acquired, severe calcification may make the leaflets almost unrecognizable.
Ventricular hypertrophy is concentric and reduces cavity size.
This is known as Williams syndrome when associated with idiopathic hypercalcemia of infancy. Discrete subvalvular AS may be a membrane or a fibrous ring just beneath the aortic valve. It is often called idiopathic hypertrophic subaortic stenosis, but this terminology is unnecessary. The septum is hypertrophied more than is the free wall. The first response to outflow obstruction is LV hypertrophy with encroachment on the chamber volume rather than external enlargement, leading to diastolic LV dysfunction.