Ischemia. This term is a desciption of the fact that the front and left sides of the left ventricle are not getting enough blood during stress situations. The left ventricle is the main part of the heart. The term reversible means that during stress this part of the heart does not get enough blood and it implies that the artery going to that part of the heart has a blockage.
Bad problem. Its a lesion that would benefit from treatment. The heart muscle is suffering but has not sustained permanent damage.