Dharana on the Heart — Direct Knowledge of the Mind
Samyama on the heart (hridaya) gives direct knowledge of the nature of the mind (chitta) — one of the most practically important Samyamas in the entire third chapter.
Sutra 3.34 states: 'hridaye chitta samvit' — from Samyama on the heart, knowledge of the mind is attained. The heart referred to here is not merely the physical organ but the hridaya — the spiritual heart center that is the seat of consciousness in Indian philosophy. When awareness is fully gathered and concentrated at this center, the structure and movements of the chitta become transparent: the yogi can see directly how thoughts arise, why they arise, what impulses drive them, and how they can be redirected. This is the Samyama equivalent of the modern therapist's ability to observe the client's mental patterns — except that in Samyama on the heart, the yogi is observing their own mind with the same directness.
From Samyama on the heart, knowledge of the mind is attained.
Neurocardiology researcher J. Andrew Armour's discovery that the heart contains a complex intrinsic nervous system — sometimes called 'the heart brain' — with its own form of memory and pattern recognition provides a physiological basis for Patanjali's claim that Samyama on the heart illuminates the mind.
Yoga Sutras of Patanjali