The values you give seem normal to me. Probably the graph gives the indication for the suspected anteroseptal MI.
Heart health is, as the health of the rest of your body, improved/sustained with healthy food, exercise, no smoking/ limited or no drinking, not too much stress etc, ..... all the usual things.
Previous damage from the MI will not go away though. Also, if the MI is caused by clogged coronary arteries, these blockages will not go away with above mentioned measures.