Heart flutter. This is usually manifested by a sensation of a skipped heart beat. We generally cannot feel our heart beat. If you do have a sensation of a skipped heart beat or palpitation, see your primary care physician for an initial evaluation and if appropriate, he/she can refer you to a cardiologist for further evaluation.
You would feel it. If you don't feel your heart flutter, you don't have to worry about heart flutter. (if a tree falls in the forest and no one hears it, did it make a sound? ).