The normal rhythmic heartbeat is called the sinus rhythm, and it is released from the sinoatrial node from pacemaker cells. In this node, an electrical signal is made that travels through the heart to cause the heart muscle to contract.
The sinoatrial node is located in the upper part of the right atrium near the mouth of the superior vena cava.[35] This electrical signal travels through the right atrium through radial routes that are not fully understood. Then it is transmitted to the left atrium via Bachmann’s bundle, and the muscles of the right and left atria contract together. [36][37][38] The electrical signal then travels to the atrioventricular node, which is located at the bottom of the right atrium in the atrioventricular septum – the border between the right atrium and the left ventricle in particular, and it is part of the cardiac structure, the tissue inside the heart that electrical signals cannot pass through, and this forces electrical signals to pass through the atrioventricular node exclusively. [9] The electrical signal then travels through the bundle of Hiss from the left branches to the right branches of the bundle to the ventricles of the heart. In the ventricles, this signal is carried by special fibers called Purkinje fibers that transmit it to the heart muscle.[39]
