Abstract: A medical lead adaptor assembly for making an electrical connection between a cardiac lead and an external medical device, with the cardiac lead including a lead connector pin for electrically coupling the cardiac lead to the lead adaptor assembly. The lead adaptor assembly includes a connector end assembly that electrically couples the lead adaptor assembly to the external device, a housing portion that has a lead receptacle portion including a lead receptacle that receives the lead connector pin of the cardiac lead to electrically couple the cardiac lead to the lead adaptor assembly, and a retaining flange that extends from the housing portion and has a retaining slot that receives and retains the cardiac lead to substantially prevent corruption of the electrical coupling of the cardiac lead to the lead adaptor assembly.