Does patent foramen ovale cause right ventricular hypertrophy? if so why?

Patent PFO: Pfo per se doesn't cause right ventricular hyopertrophy unless until there is any associated pulmonary valvular/ sub or supra valvular stenosis.

ASD=RV volume load: This may be a matter of semantics/terminology. Sometimes, patients with an atrial septal defect (ASD) are labeled as having a patent foramen ovale, as both lesions occur in the same spot. If there is an asd, there can be sufficient left-to-right shunting at the atrial level, resulting in rv volume overload, rv enlargement and rv hypertrophy.