The pads (flattened stem segments) of Cactus Apples or Engelmann's Pricklypears (Opuntia engelmannii) are normally rounded and shaped very much like ping pong paddles. Damage early in a pad's growth can cause it to become oddly shaped, and it's not that uncommon to find damaged, heart-shaped pricklypear pads like this one.
Both the de-spined pads and the fruits of this abundant cactus are edible. The pads are a bit slimy, but the fruits are sweet and juicy. The ripe fruits are more of a deep red color, so these pink fruits are not quite ripe yet.