Carotid upstroke is decreased (pulsus parvus) and late (pulsus tardus) because of the fixed obstruction to flow. Left ventricular hypertrophy causes the apical impulse to be displaced laterally and to become sustained. The increased dependence on atrial contraction is responsible for the prominent S4. Flow through the restricted aortic orifice results in the midsystolic murmur, whereas regurgitant flow causes the diastolic murmur.