What Energy makes the human heart beat once?

The energy that makes the human heart beat once is electrical energy. The heart's electrical system is responsible for coordinating the contractions of the heart's chambers, which pump blood throughout the body. The heart's electrical impulses are generated by specialized cells called the sinoatrial (SA) node and the atrioventricular (AV) node. The SA node is located in the right atrium, and it is responsible for generating the electrical impulse that triggers the heart to contract. The AV node is located between the atria and the ventricles, and it delays the electrical impulse slightly to allow the atria to fill with blood before the ventricles contract. The electrical impulses from the SA and AV nodes travel through the heart's conduction system, which is a network of specialized fibers that carry the electrical impulses to all parts of the heart. The electrical impulses cause the heart's muscle cells to contract, which pumps blood out of the heart and into the body.