The suttas are a little ambiguous on this point. Generally speaking, the two are presented together, and represent two aspects of arahantship, resulting from the paired development of samatha and vipassana. However in a few places they seem to be at least partially distinguished, correspodning roughly to those who prioritize samatha and those who prioritize vipassana.
In addition, “release of heart” is used in a distinct sense to refer to samadhi, especially the brahmaviharas.