This is a condition where the left side of the heart muscle is too thick..
Can this be reversed?
I read it can be?
Yes, it can be reversed if the cause is corrected. Think about it this way. When you exercise you build muscle mass. When you stop exercising the muscle atrophies. Again the heart is a muscle. But one side of the heart is being made to work harder causing the muscle to increase in size, just like when you exercise to build skeletal muscle. If the source of the resistance or whatever is causing the heart to work harder than normal is removed the heart muscle will start returning to normal since it no longer has to work as hard as it had to.