Hi, first of all I hope that you are aware about the fact that palpitations occur in normal people too but here it is almost always caused by a concentration on the beating of one's heart, especially during exertion, exercise or certain drugs. In your case it is difficult to say whether the palpitation is due to an underlying disease or not. Your GP is right about the heart rate, it is heigh. The rhythm needs to be evaluated by an expert at heart diseases