The<unk>  is the size of the orifice for blood to flow from the left ventricle to the aorta.  The<unk>  is reduced in<unk>  stenosis, and the<unk>  is the metric that is used to gauge the need for<unk>  valve replacement surgery.  The pressure gradient across a narrowed<unk>  valve cannot be used to gauge the need for valve replacement as the gradient may be low in patients with impaired left ventricular function.
Aortic valve area
Anatomy of the heart left atrium
Left ventricular end diastolic pressure
Guidewire tip diameters
Ventricular pressure
Electrical conduction system of the heart
Anatomy of the heart right ventricle
Cusps of heart valves