After Angioplasty Outcome. Me sir. plss!

My mother had heart attack on 29oct. Before that she had anginal pain but after start management with medicine for 2 months She had no discomfort but after angiography doctor said she had 85 % blockage of lcx om artery.and they done angioplasty but after 1 month my mom lvef decreased to 32. After heart attack and even after 2 month of medical treatment it was stable on 45.i don't know why it's drop by 13 percent in just 1 month after stenting... After heart attack my mom dimension of left atrium and left ventricle was normal and it was normal after 2 month before angioplasty.but one month after angioplasty 2d echo shows that dimensions of left atrium and left ventricle shown dilated.i was expected better outcomes after angioplasty.but these results made me relentless.i have only my mother left...please guide me sir...plsssssss