mike: there's some other causes of hypertrophic cardiomyopathy there's the septal cause (most use to), also mid-cavitary lesion (someone with an aneurysm - bottom-right) this is somewhat common in our elderly patients, where you actually see that instead of the mv acting at the dynamic outflow obstruction, it's the center of the cavity for one reason or another (secondary to hypertension usually) causes the obstruction.