Electrical conduction
Main article: Electrical conduction system of the heart
The normal rhythmical heart beat, called sinus rhythm, is established by the sinoatrial node, the heart's pacemaker. Here an electrical signal is created that travels through the heart, causing the heart muscle to contract.
The sinoatrial node is found in the upper part of the right atrium near to the junction with the superior vena cava.[24] The electrical signal generated by the sinoatrial node travels through the right atrium in a radial way that is not completely understood. It travels to the left atrium via Bachmann's bundle, such that both left and right atria contract together.[25][26][27] The signal then travels to the atrioventricular node. This is found at the bottom of the right atrium in the atrioventricular septum–the boundary between the right atrium and the left ventricle. The septum is part of the cardiac skeleton, tissue within the heart that the electrical signal cannot pass through, which forces the signal to pass through the atrioventricular node only.[7] The signal then travels along the Bundle of His to left and right bundle branchesthrough to the ventricles of the heart. In the ventricles the signal is carried by specialized tissue called the Purkinje fibers which then transmit the electric charge to the cardiac muscle.[28]
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