Defibulator implanted in their heart, can that person have intercourse without a lot of fear?

Depends: The presence of the defibrillator itself is not the issue. Persons with a defibrillator have some type of heart disease, most commonly a weak heart muscle. The type of and extent of that disease would determine the advisability of exercise including sexual intercourse. So your physician needs to advise you. Would not want defibrillator to fire during sex, you know. That could be quite a shock!

Yes: A lot of people with icds have a normal sex life. Just make sure you tell your ep nurse that usually checks your icd to make sure that the detection rate for shocks should be adjusted so you can have a normal heart rate increase (i.e. Sinus tachycardia) with activities, including sex. She can easily program this into the icd to avoid inappropriate shocks.