Understanding how a revolver clasp works makes operating it straightforward. A cylindrical barrel rotates around a fixed tongue to open and close, so the motion you're looking for is a twist, not a push or pull.
Visually Speaking
Symbolic pendants ask to be read. The concealed bail enhances the visual focal point of the piece by routing the attachment behind the pendant, making the symbol the first thing the eye sees.
A Storied Heritage
The sacred heart's influence on European heart jewelry design gives antique heart pendants and devotional pieces in that tradition a specific religious meaning that the modern secular heart does not carry, which adds historical depth to a heart piece chosen for its connection to that tradition.