Hṛdaya dhauti is connected to mūla bandha, the root lock. There is terminological ambiguity here: mūla bandha generally refers to the contraction of the pelvic floor, but in this context it seems to imply a technique connecting the base of the throat (kaṇṭhamūla) with the cardiac center.

The verse suggests there is an energetic line or channel connecting these points, and that the “application of the lock” (bandhena bandhanāt) purifies the cardiac region.

This technique, like many in Haṭha Yoga, operates at the interface between physical anatomy and the subtle body.