Normally, the heart is signaled to contract, or squeeze, by an electrical impulse that starts in the sinus node at the top of the right atrium. The impulse then travels through the heart’s “wires,” to the muscles of the lower chambers of the heart (right and left ventricles), telling them to contract and cause a heartbeat. This natural system helps the heart pump in an efficient rhythm. A problem with any part of this system, though — either the heart’s natural “pacemaker” or the wires carrying the impulses — can cause a slow heart rate. An artificial pacemaker may be needed to reset the heart to the right pace and make sure blood and oxygen are pumped to the brain and other parts of the body.
Credit: Heart Rhythm Society