Normal Cardiac Long Axis View
Echo Long Axis View
The labeled still image ("Normal Long Axis") is a still frame from an echocardiographic long axis view, a tomographic slice from the left ventricular apex to the base of the heart.   The labels represent:

  IVS - interventricular septum
  LV - left ventricular cavity
  LA - left atrium
  RV - right ventricle (a portion of its outflow tract)

PW - posterior wall of the left ventricle
Ao - aortic root
A - Anterior
C - Cephalad

The arrow points to the closed aortic valve plane.  The mitral valve is open (is this in diastole or systole?).

Now open the video clip labeled "Normal AV" to see normal aortic valve motion.

Open and compare that clip to the "Stenotic AV" clip.  Notice the thickening of the valve leaflets and the limited valve excursion.  This is a bicuspid aortic valve in a 40 year old man with mild aortic regurgitation and severe aortic stenosis.