How to use an element text as. Running H/F based on the value of an attribute?

We want to use a system variable in the header of a master page based on the value of a Title's attribute (or Context label). For instance we have a chapter made up of sections. Each section has its own title. We want to use the Title of the first section in the header of the pages.

In the EDD is defined that the Title of the first Section gets a Context label H1.

Should we define the Running H/F 1 like <$elemtextonly[Title:H1]> or something? Or <$elemtextonly[Title:[Type:H1]]> ??

How to do this?