I have been diagnosed with apex of the heart death. what does that mean? what treat meant will be possible, diet changes, what not to do to prolong my life?

Clarify: You have both a right and a duty to get more precise information from your physician. If you have had a heart attack involving the apex, you need to know this, with its implications. If you merely had stunned / deadened myocardium / takotsubo, you'll be fine. A precise diagnosis will enable your physicians and the healthtap team to clarify, and even better, let know know your best course.