Murmur of Aortic stenosis

The murmur of Aortic stenosis is characteristically

1. Ejection (mid)systolic murmur which  commences shortly after the S1,it increases in intensity and reach  a peak towards the middle of ejection, and it ends just before closure of aortic valve. 
2. It is a diamond shaped systolic murmur.
3. It is characteristically low-pitched, rough and rasping in character. 
4. The murmur is  loudest at the base of the heart, most commonly in the second right intercostal space.
5. Aortic stenosis murmurs is transmitted upward along the carotid arteries. Occasionally this murmur is transmitted downward and to the apex, it may be confused with the systolic murmur of MR. This phenomenon is called Gallavardin effect.
6. In patients with severe obstruction and normal cardiac output, the murmur is at least grade III to VI.
7. If patient  has mild degree of obstruction or in those  patients with severe stenosis with heart failure and low cardiac output the transvalvular flow rate are reduced, the aortic stenosis murmur may be soft and brief.