- Firstly, there is significant ventricular hypertrophy. More muscle requires more blood flow, but unfortunately, the coronary vessels don't enlarge or branch adequately to compensate.
- Secondly, the left ventricle has to pump with greater force in AS, due to the increased resistance to the outflow of blood that attends the condition. A greater muscular effort similarly requires more blood flow.
- Lastly, the vessels to the myocardium are compressed to varying degrees during systole. With the increase in contractile force seen in AS, the vessels are compressed more severely than before, thus permitting less blood flow to the heart.
Hope that helps!