Define HOCM Murmur characteristics in details?

Characteristics: The murmur is harsh, crescendo-decrescendo audible along the left sternal border, radiates to the base of heart but not well-appreciated over-the carotids.

Systolic ejection clicks are absent.

The obstruction in HOCM is due to the hypertrophied septum-which bulges into the LVOT during systole together with systolic anterior motion of the anterior mitral leaflet (Bernoulli effect). Both these contribute to make the LVOT narrow.

The murmur increases intensity with any manoeuvre that reduces left ventricular cavity size or increases contractility like valsalva manoeuvre, administration of amyl nitrite, beat following a VPB.