The heart is a muscle that pumps blood and distributes it throughout the body via a network of arteries and veins, supplying the tissues with oxygen, nutrients and various other health- and life-sustaining biochemical compounds. read more...

The normal rhythm, called sinus rhythm, originates from a natural pacemaker, the sinoatrial (SA) node, located in a chamber of the heart, the right atrium. At rest, approximately every second, this pacemaker fires and sends an electrical signal that spreads throughout the heart muscle and makes it contract. read more...