3 or 4 heart palpitations per day, feels like a single strong beat. had echo and ekg 2 years ago, both normal. no other symptoms with them, healthy otherwise. benign?

It doesn't appear to be a serious issue. You may be experiencing occasional premature heart beats. The next normal beat after the premature beat& the pause is more forceful than the usual normal beat and this is what you may be feeling. To determine the nature of your palpitations you'll have to wear an outpatient cardiac monitor for 48 hours or longer. Discuss this with your physician.