An early systolic murmur may be caused by all of the following, EXCEPT:
In Aoic stenosis, murmur is ejection systolic ie: murmur stas after the isovolumic or isometric contraction phase. So the murmur stas only after the opening of the semilunar valve. In all the other conditions murmur stas in the isometric contraction phase itself, so its early systolic.
Small ventricular septal defect
Papillary muscle dysfunction
Tricuspid regurgitation
Aoic stenosis