Kitzur Shulchan Aruch (Ganzfried) 67:6 states:
"A vow does not take effect unless one's words and one's heart agree. However, if one made a vow by mistake, not intending to say what one did say, or thought about making a vow, but did not say it out aloud, this is not a vow."
I am looking for more information about error of intention when someone pronounces a vow. What is the source, and what are the implications, of this ruling in the Kitzur Shulchan Aruch, and is it generally accepted as normative Halacha?