This article only suggests what could be the control of the mind and breath in Christian mystical meditation, in the vision of Abheda Yoga (and therefore not in the vision of an Orthodox authority, with which, however, it could coincide).
But thus, we say that it only suggests, because these practical aspects cannot be learned from a few explanatory lines and the best way is direct guidance from a competent person.

The holy fathers had long known the breath-mind relationship, namely that a restless breath denotes a restless mind.
The control of breathing has the role of mastering and bringing peace of mind. Breathing techniques are very common in the holy fathers.

'Qn state of deep reflection the movement of the breath slows down... as for breathing, they (those who practice) they reduce it as much as possible. These effects then follow spontaneously in the practice of Christian meditation of the heart."
St. Grigore Palama in the work Defending Saints Isihasti.

Also here Grigorie Sinaitul recommends:

"Master the movement of your lungs so that you do not breathe freely, for the storm of breaths that ascends to the heart darkens the mind and disturbs the thought. And if you see the uncleanness of the thoughts, do not pay attention to them, but as long as you can stop your breath; close your mind in your heart and continue the call of the Lord Jesus".

It is recommended to hold the breath after the prayer and the deep contemplation of the peace of mind that appears then, because all Gregory sinaitul says:

"Retaining the breath rules the mind but only in part. But when the work of prayer also comes, the mind will be truly mastered" from the work on the contemplative life.

"That is why some teach to master the movement of their breaths and to hold it a little, so that the mind may stand still while they keep their breathless... reaching to bring it perfectly to the state of unifying concentration."
Gregory Palama

Mind and breathing control in mystical isihast meditation is simple but powerful.