A palpitation is an abnormal awareness of the beating of the heart,[1] whether it is too slow, too fast, irregular, or at its normal frequency. It can be caused by (but should not be confused with) ectopic beat, which is a more specific diagnosis. It is also the associated characteristic of angina.
The difference between an abnormal awareness and a normal awareness is that the former interrupts other thoughts, whereas the latter is almost always caused by a concentration on the beating of one's heart.

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