No not usually; palpitations are simply an awareness of ones own heart beating. They are usually benign and do not generally represent pathology. Common causes are stress/anxiety
and caffeine. If you are frequently suffering from panicky episodes then your GP can refer you for CBT (Cognitive Behavioural Therapy).
If you are experiencing any other symptoms with these episodes such as pain etc then your GP will probably want to do a 24 hour ECG trace. It might also be worth checking your thyroid