Heart is one of the most iconic organs in our body. It is the hardest working muscle. It powers the entire circulatory system-constantly transporting oxygen, nutrients, waste, heat, hormones and immune cells throughout the body. For most of history, humans had no idea what purpose the heart served. Although everyone could feel their own heart beating, it wasn't always clear what each thump was achieving. Now we know that the heart pumps blood, but that fact wasn't always obvious because if our heart was exposed or taken out, the body would perish quickly. It was only in the 21st century, that the people in the surgery teams actually saw a working heart. Healthcare experts advise people to care for the well-being of this life sustaining organ, since it is vulnerable to various physical and emotional factors. Researchers have presented various studies that have shown the functioning of this essential organ and the conditions that can disrupt that normality. 51 Must Know Facts about Heart sums up the entirety of various fascinating heart related aspects that are crucial to understand when our entire existence is dependent on this vital organ.