Unpleasant sensations of irregular and/or forceful beating of the heart. In some patients with palpitations, no heart disease or abnormal heart rhythms can be found. In others, palpitations result from abnormal heart rhythms (arrhythmias). Arrhythmias refer to heartbeats that are too slow, too rapid, irregular, or too early.
Your pulse is bounding fair like it's trying to jump out of you, it doesn't have a nice rhythm to it and you swear you are at least having a heart attack. But… surprise, surprise, it's just another CFS symptom.