The GetPipelineItemsAttachedToContact function is used to retrieve a list of all pipeline items that have been attached to a contact. For example, if you have a "Lead" pipeline and you attach a lead to a contact, this function will return the info associated with that lead.
If successful, this function will return an array of pipeline items. Each pipeline item will contain information about that specific item include the PipelineId (e.g. the Id corresponding to the "Lead" pipeline), the PipelineItemId (e.g. the Id corresponding to this particular lead) and information about the pipeline item such as the status and custom field values.
ContactId - The Id of the contact you want to retrieve the pipeline items for