The heart of an average human beats approximately 2.5 billion times over the typical lifetime of 70 years. This equates to pumping about 51,100,000 gallons of blood.
Normally, the heart beats regularly throughout every day and night of a human's life. It is the center of circulatory system, which transports nourishing blood cells rich in oxygen throughout the body before bringing them back to be re-oxygenated.
The four chambers of the human heart must operate in a precise manner or blood stops circulating, a process controlled by electrical signals that cause each chamber to open and close on schedule. When these signals aren't operating correctly, abnormal heart beats called arrhythmias occur, which can be dangerous or innocuous.