Base Right: Severe Aortic Stenosis Murmur
A midsystolic murmur begins shortly after the first sound, peaks in the middle of systole, and does not quite extend to the second sound. It is also known as ejection murmur. The most characteristic feature of this murmur is its cessation before the second sound, thus leaving this latter sound identifiable as a discrete entity. This type of murmur is commonly heard in normal individuals, particularly in the young who usually have increased blood volumes flowing over normal valves.
Obstruction or stenosis across the aortic or pulmonic valves also may give rise to a murmur of this type. These murmurs are louder and longer than the innocent murmur, and reach a peak intensity in midsystole. The murmur of aortic stenosis is harsh in quality and is heard equally well with either the bell or the diaphragm. It is heard best at base right and radiates to the apex and to the neck bilaterally.
The sound you heard is an example of a murmur typical of severe aortic stenosis.