I imagine most animals, plants, and sentient beings pay little notice to the shape of a heart. It is a very human thing to recognize the heart in something. After all, when you remove the heart to examine it does not very much resemble the symmetrical two-portioned stack it has come to symbolize today.
The body could not live without the heart. The heart is different from the brain, in that it pumps blood. The heart is the source of rhythm and vibration, albeit dependent on the brain's neural activity and electrical impulses. It is a strong muscle moving about crimson iron and nutrients to the rest of the body; a mysterious thing. The heart is a source of rhythm, a natural timer. When the heart beats faster you are usually moving faster, or getting ready to! The heart can be quieted, silenced, comforted, broken, and even pierced by an arrow.
What other visual coincidences might you encounter in your everyday?