Disclaimer: I am fully aware that Desperate Housewives has no intention of being scientifically accurate, so I would prefer not to have this information as an answer.
In the episode "The Best Thing That Ever Could Have Happened" (S05E13), Eli Scruggs (played by Beau Bridges) has a heart attack on the roof, right after he finished the repairs.
However, when the pain hits, it is on the right side of his body, instead of the left. It was OK (scientifically) that the pain was located near the shoulder, but why did they choose to hint that the heart is on the right side of the body?
I could speculate that for some reason they flipped the image, so the left became the right, but I have no reference that this could be the case.