Your heart normally beats about 100,000 times a day, which translates to 60-100 beats per minute. It does this in an orderly fashion, controlled by a steady stream of electrical impulses.
The heart consists of two upper chambers, called the atria, and two lower chambers, called the ventricles. Electrical impulses that coordinate the heart’s contractions originate at the sinoatrial node — also called the sinus node or SA node. The SA node is a bundle of highly specialized cells in the right atrium.
The signal passes through the right and left atria, telling them to contract. When the atria contract, oxygen-rich blood is pushed into the ventricles. Then the atrioventricular node, or AV node, receives the signal and passes it into the ventricles, telling them to contract. When the ventricles contract, blood is pumped out of the heart into the body.