When to call doctor about palpitations / flutter?

Palpitations: When does one worry about palpitations? Two things to consider: 1) accompanying symptoms. If feeling faint, severe shortness of breath, or severe chest pain then it's probably best getting i checked out. 2) duration of palpitations. If racing heart beats go on and on for hours or days, best getting i checked out.

Now: Palpitations should be checked. Some are more serious than others and you cannot know unless they are captured on an ecg, which would be by chance mostly. You may need to wear a heart monitor for some time to see the rhythm when you have the feeling.