Have you been checked by a doctor?
Skipped heart beats need to be checked to determine if there is any heart problems.
With the little you have told us, it is impossible to reach any conclusion. All of us are at some risk of having a heart attack. Your question seems to be looking for a number. I don't think anyone can give you one, but I think it unlikely you will have a heart attack any time soon if you are able exercise and don't have any other warning symptoms.
You may want to consider taking an aspirin a day (low/partial dose of full dose) to gain a small measure of protection. I take my 1/2 regular aspirin in the morning with breakfast. My stomach doesn't have any problems with aspirin, yet.