Can ginseng cause heart palpitations?

Yes: There are many causes of palpitations, so in an individual case it could be something else, but ginseng is a stimulant and has been reported to be responsible for palpitations. It would be advised to try stopping it and see what happens.

Stimulant-yes: There have been reports of palpitations with stimulant type supplements causing palpitations (example ginkgo). Ginseng affects a lot of people in variable ways, and in many might have a mild stimulant effect. Would not be surprised if that could result in occasional palpitations in someone so predisposed