What I said is not Pranayama. Its natural breathless stage. Kriya Yoga Pranayama deals with this. And Pranayama - if you follow Ashtanga Yoga, Hatha yogic process, pranayama is must before Dhyan.
If you follow Raja Yoga, mantra yoga, these paths - dont deal with external breath. They deal with cleansing the mind, and focusing on Paramatma and Pranayama is a part of this process and not seperate limb like how Pranayama is part of Sandhyavandanam...