Atrioventricular fasciculus

The atrioventricular fasciculus, traditionally known as the bundle of His, is an intracardiac formation consisting of a thin cord of muscular nature, approximately 1 cm in length, which forms part of the conduction system of the heart, through which the excitation of the atria is transmitted to the ventricles.

Two parts can be distinguished in it: the short, perforating segment, about 5 millimeters, which crosses the fibrous trigone, and the inframembranous segment, which runs along the perimeter of the postero-inferior quadrant of the membranous portion.

It originates in the Tawara node located in the right atrium and runs along the inferior surface of the interatrial septum. The inframembranous segment after a short path along the interventricular septum divides into two branches: the right and the left. The last leads of the bundle of His extend through the ventricular endocardium, forming the Purkinje network (subendocardial network).

Cardiac automatism

The electrical impulse originates in specialized cells, pacemaker cells, which are grouped in the right atrium next to the superior vena cava, which constitutes the sinus node. From there the stimulus is distributed through both atria until it reaches the other node (atrioventricular node). From this point on, the excitatory stimulus is conducted by a system of specialized fibers, the Purkinje fibers, organized in a bundle that runs through the interventricular septum: bundle of His.