I just discovered two pop songs based on the main theme of Dressed to Kill, presumably recorded for the Japanese LP of the soundtrack. Since I can find no information about the tracks other than the lyrics were written by a woman named Carol Connors (no relation to Thora Birch's porn star mother, I'm sure), I'll just stick with that theory. The Japanese LP of Blow Out – itself an interesting lounge re-recording of the score – also featured two such songs, though they were not derived from Pino Donaggio's music. Japan sure loves pop music on their soundtracks, even if the songs weren't actually in the movie at all. (Sometimes, as was the case with Tenebre, they put a pop song over the end credits of the film without the filmmakers' knowledge.) Who knows why they do this, but it gives me something to post about so what the hell. If anyone knows the origin of these tracks, please fill me in. Listening to them, I find myself relieved that they were never used in the movie.
Update (3/21/13): It turns out that the song comes from an Italian 7" single, not a Japanese single as I originally stated. The B-side is "You Don't Have to Say You Love Me," (aka "Io Che Non Vivo"), a pop song written and recorded by Pino Donaggio in the 60s and made famous by Dusty Springfield. So where does the second version of "How Was My Heart to Know" come from? Perhaps there's single out there with a different B-side. It's so strange how these super rare movie-related singles keep popping up out of nowhere.