Palpitation could be due to cardiac weakness, general debility, blood-pressure, use of strong medicines or suffering from shocks; treatment for all is one with slight change to the method for every cause.
For occasional palpitation recite the following 3 times, blow upon some water and make the patient drink this water.

If resulting from shocks in life, palpitation has become a regular feature write the above words on a piece of paper, put it in a bottle of natural honey and make the patient to use from this honey at least 3 times a day.
If palpitation is because of the High-Blood Pressure then instead of plain water use sugar added water and make the patient to drink it early in the morning on empty stomach.
If it is due to Low Blood-Pressure recite the above and blow in the bottle of table salt and make the patient to use this salt.
If the reason of palpitation could not be determined get the word اللّہ written on a large paper with black ink in beautiful handwriting and paste this paper on a hardboard. Before going to bed at night place this hardboard where nobody else is present. Look at this Appellation intently for a minute or so, close your eyes and imagine that effulgent lights of Allah are showering upon you. Let this imagination be there for about 10-15 minutes. Open your eyes and go to sleep without talking to anyone. Practicing this for a few days would cure the palpitation permanently by the grace of Allah.