According to information I found on reputable medical sources, regarding these common heart palpitations, heart disease is not
the most common cause of PACs. If that were the case, the estimated 50% of the general population, believed to have relatively frequent PVCs/PACs, would all be walking around with heart disease.
AS far as MS causing PACs, I have no direct knowledge that this is true nor have I ever heard of someone in this forum ask that question. Please do mention your concern to your Dr.