no, any prayer you memorise and repeat sincerely can repeat itself inside you after you stop thinking about it.
just think, if you listen to a popular piece of music many times a day (eg. on the radio), the tune will be inside your head the next day as you are travelling or resting.
you will not be able to stop thinking about it easily.
how much better, then, to memorise prayers and passages from the Bible, so that they will be going around in your head after you finish thinking about them.
so when we find the sincere prayer going around and around in our head, we call it the prayer of the heart, because we have become so full of this prayer that we think about it without realising it.