Where is atrioventricular bundle located

In general, the atrioventricular node is located in the so-called floor of the right atrium, over the muscular part of the interventricular septum, inferior to the membranous septum: i. Following atrioventricular nodal excitation, the slow pathway conducts impulses to the His bundle, indicated by a longer interval between atrial and His activation.

Currently, there is interest in the ability to place pacing leads to preferentially activate the bundle of His; in such approaches, ultrasound or other imaging modalities are used to map the electrical characteristic His potentials to position the pacing leads [20]. After leaving the bundle of His, the normal wave of cardiac depolarization spreads first to both the left and right bundle branches; these pathways rapidly and simultaneously carry depolarization to the apical regions of both the left and right ventricles see Figure 1.

Finally, the signal broadly travels through the remainder of the Purkinje fibers and ventricular myocardial depolarization spreads. In certain pathological conditions, direct accessory connections from the atrioventricular node and the penetrating portion of the bundle of His to the ventricular myocardium have been described [21]. Yet, the function and prevalence of these connections, termed Mahaim fibers, is poorly understood. A rare bundle of Kent, an additional aberrant pathway when present, exists between the atria and ventricles and is associated with the clinical manifestation of ventricular tachycardias also known as Wolff-Parkinson-White syndrome.

Therapeutically, this accessory pathway is electrically identified and then commonly ablated as a curative procedure. The left bundle branch splits into fascicles as it travels down the left side of the ventricular septum just below the endocardium. Its fascicles extend for a distance of 5 to 15 mm, fanning out over the left ventricle. Importantly, typically about midway to the apex of the left ventricle, the left bundle separates into two major divisions, the anterior and posterior branches or fascicles.

These divisions extend to the base of each papillary muscle as well as the adjacent myocardium. In contrast, the right bundle branch continues inferiorly, as if it were a continuation of the bundle of His, traveling along the right side of the muscular interventricular septum. This bundle branch runs proximally, just beneath the endocardium, and its course runs slightly inferior to the septal papillary muscle of the tricuspid valve before dividing into fibers that spread throughout the right ventricle.

The complex network of conducting fibers that extends from either the right or left bundle branches is composed of the rapid conduction cells known as Purkinje fibers. Purkinje fibers in both the right and left ventricles act as preferential conduction pathways to provide rapid activation, so to coordinate the excitation pattern within the various regions of the ventricular myocardium. Most of these fibers travel within the trabeculations of the right and left ventricles, as well as within the myocardium itself.

Due to tremendous variability in the degree and morphology of the trabeculations existing both within and between species, it is likely that variations in the left ventricular conduction patterns also exist. Furthermore, in many human hearts, within both the right and left ventricles, one can identify conduction bands that are white in appearance e. In , Aschoff and Monckeberg provided three criteria for considering a myocardial cell as a specialized conduction cell, including: 1 the ability to histologically identify discrete features; 2 the ability to track cells from section to section; and 3 insulation of the cell by fibrous sheaths from the nonspecialized contractile myocardium [22,23].

It is noteworthy that only the cells within the bundle of His, left and right bundle branches, and Purkinje fibers satisfy all three criteria. Sign up. Illustrated anatomical parts with images from e-Anatomy and descriptions of anatomical structures.

The bundle of His is a collection of heart muscle cells specialized for electrical conduction that transmits the electrical impulses from the AV node located between the atria and the ventricles to the point of the apex of the fascicular branches via the bundle branches. The bundle of His branches into the left and the right bundle branches, which run along the interventricular septum.

The left bundle branch further divides into the left anterior and the left posterior fascicles. These bundles and fascicles give rise to thin filaments known as Purkinje fibers. These fibers distribute the impulse to the ventricular muscle. The ventricular conduction system comprises the bundle branches and the Purkinje network. It takes about 0. IMAIOS and selected third parties, use cookies or similar technologies, in particular for audience measurement.

Cookies allow us to analyze and store information such as the characteristics of your device as well as certain personal data e. For more information, see our privacy policy. The nonbranching bundle passes through the central fibrous body and is surrounded on all sides by the central fibrous body. In this cardiac region, the His bundle still has atrial tissue superior and anterior to it, the ventricular septum inferior to it, and now the aortic and mitral valves posterior to it. It should be noted that His myocytes are innervated, but to a lesser extent than those in the atrioventricular node.

Unlike the sinoatrial and atrioventricular nodes, the His bundle has no large blood vessels that supply it specifically. The common branching bundle is described to begin as the His exits the central fibrous body.

At this point, it is inferior to the membranous septum and superior to the ventricular septum. After leaving the central fibrous body, it then bifurcates into the right and left bundle branches. The right bundle branch passes within the myocardium of the interventricular septum and the left bundle branch primarily travels subendocardially along the septum in the left ventricle as noted above.