St. Ignatius of Loyola teaches a method similar to the mantra which he calls "rhythmical prayer" (see The Spiritual Exercises, "Third Method of Prayer"). The difference is that he recommends using the rhythmical method described under #1 of the mantra on each word or sense-unit of some common prayer -- for example, saying one word of the Our Father with each breath, and in the time between each breath concentrating on the meaning of the word, or on the person being addressed, or on one's own lowliness and need, etc. In this way one can go through a whole prayer or several prayers during the time set aside for this exercise.