Actually, Atropine is fundamentally used to inhibit muscle action, which is why it is useful for treating the aforementioned cardiac symptoms, dilating pupils, among other needs.
Another common use is as an ingredient component in Lomotil (Lonox), which is used to treat diarrhea. It reduces the spasming, or motility, of the bowel, which when combined with the inherently constipating action of its narcotic component, diphenoxylate hydrochloride.