the joke went over his head, let him be dumb.

I think he meant smth else because it should've said "is experiencing" not "developed".

Heart attacks are what happens when blood can't return to the heart because something blocked it and, thus, the heart muscle cells start dying due to no oxygen making back to the heart. This can happen in ANY living organism that has a circulatory system consisting of a heart, arteries, and veins.

That includes simple animals like reptiles!