What do you mean by "palpitations"? A couple of PVCs, feels like skipped beats, probably doesn't mean anything, but a run of tachycardia does need to be investigated.
If they are persistent your doctor can prescribe a Holter Monitor for you to wear for a day to record the beats so he can look at the EKG while they are happening. I frankly have no confidence in stress tests, as I had a heart attack shortly after having that test - which I "passed." I nearly had a second attack shortly after passing a follow-up stress test, but insisted there was something wrong and during an angiography they found I needed a second stent.