I have been told that the left side of my heart lining is becoming thicker, what does this mean?

LVH. I believe you are referring to left ventricular hypertrophy (LVH). This is thickening of the left great chamber of the heart and one frequent cause is high blood pressure. Continue to follow this with your doctor who will evaluate other risk factors you have. In some cases, this may be reversible with identification and treatment of the cause.