"We are pleased to inform you that your visa(s) for permanent residence to Canada is/are ready to be issued, conditional to a final admissibility review by an immigration officer.".....
They are ready to issue you the visa, but the decision is conditional and will be based on final admissibility review by immigration officer i.e. your medical results. Medical is one of the admissibility requirement to get Permanent residency. Even though they have requested your passport, but they will not issue you the visa until they will get your medicals.