His bundle

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blue: sinus node, red: AV node, bundle of His, Tawara limb and Purkinje fibers

The His bundle or His bundle (Latin fasciculus atrioventricularis ), named after the internist Wilhelm His , is part of the excitation conduction system . It is distal to the atrioventricular node towards the apex of the heart .


The 0.5 to 0.8 cm long bundle of His usually runs as the only muscular bridge between the atria and chambers of the heart skeleton . It "pierces" the trigonum fibrosum dextrum (a gusset filled with connective tissue in the center of the heart skeleton) and then divides into a right and left limb (tawara limb), which run to the right and left of the heart septum and into the Purkinje discovered by Jan Evangelista Purkyně -Fibres run out.


Histologically , the bundle of His consists of a collection of special heart muscle cells. These have the ability to conduct the excitation further and to spontaneously depolarize , whereby the frequency of 20-30 beats per minute is much lower in humans than in the sinus node (nodus sinuatrialis) or in the atrioventricular node (nodus atrioventricularis) .


The excitation arises in the sinus node and reaches the atrioventricular node. There is no direct connection between the two nodes, so that excitation is transmitted here via cardiac muscle cells. From there the excitation reaches the bundle of His and from there via the tawara thighs into the Purkinje fibers. All other components of the conduction system also have the ability to spontaneously depolarize . Since excitation is generated more quickly in the sinus node, it imposes its higher frequency on all other parts of the excitation conduction system, so that their ability is normally not used. However, if the sinus and atrioventricular nodes fail, the bundle of His forms its own rhythm of 20-30 excitations per minute. This is also known as the chamber replacement rhythm .


A malfunction is e.g. B. the bundle of his block. This is a cardiac arrhythmia caused by ischemic, inflammatory or primarily degenerative disease of the bundle of His. A very rare dysfunction in newborns, except after cardiac surgery, is junctional ectopic tachycardia, or bundle of his tachycardia . Electrocardiographically, it is characterized by tachycardia with normal ventricular complexes with atrioventricular dissociation. It is also based on an ectopic center of gravity located in the bundle of His.