What other medicines are there for panic attacks n anxiety I'm using citalopram but causing palpitations and irregular heart beat. Thanx!

There are many. Palpitations are a more common sign of anxiety than they are a side effect of the medicines used to treat anxiety. A heart monitor could be useful to help diagnose the source of your palpitations. Thatch go a long way in making you feel better. Knowing what is happening can be empowering.
Trial and error. Its often a trial and error but maybe Paxil (paroxetine) ( paroxitine) may be useful. Taken every day to prevent the attacks instead of treating them after they occur. Chk with your dr.