The heart is a hollow, muscular organ in vertebrates responsible for pumping blood through the blood vessels by repeated, rhythmic contractions, or a similar structure in annelids, mollusks, and arthropods.
I have been suffering with palpitations where my heart rate has gone up to 142. Now over the last month my resting heart rate has gone down to 51. I wonder how low it is while since sleep? I guess I better get it checked. I am so tired and no energy. Anyone else have a low heart rate.