For some insight there are various types
of MVP and broadly it can be classified as classic and nonclassic.... In its nonclassic form, MVP carries a low risk of complications.... In severe cases of classic MVP, complications include mitral regurgitation, infective endocarditis, congestive heart failure, and—in rare circumstances—cardiac arrest, usually resulting in sudden death...worst case scenarios.
If serious you would have shortness of breath with very little exertion.