Losing my muscle mass

Patient: I am slimming down fast that I need to buy my pants once in every 3 months. I have lost weight also but not much (maybe 2 kilo in 3 months). May I know why?EDIT:I do not have thyroid issue. However, I have had a stent placed in 2007 for a cardiac attack. Since then, I have normal life, doing exercise and moderate food.

Symptoms: My thigh muscles are become slim. My feet also has shrunk.