The atrioventricular node, or AV node, electrically connects the atria and ventricles of the heart to coordinate the beat in the upper heart of the heart; It is part of the electrical conduction system of the heart. [1] The AV node is located in the inferior posterior part of the interatrial septum near the opening of the coronary sinus and conducts the normal electrical impulse from the atria to the ventricles. The AV node is quite compact (~1 x 3 x 5 mm). [2] Tum extrema pars eius inferioribus acu assuenda est; Nam nodus vulnus laedit, nisi tamen loin est (c. xxvi). The AV node is located in the inferior posterior part of the atrial septum, near the opening of the coronary sinus, which conducts the normal electrical impulse from the atria to the ventricles. The AV node is quite compact (~1 x 3 x 5 mm). [2] It is located in the center of Koch`s triangle – a triangle surrounded by the septal leaflet of the tricuspid valve, the coronary sinus and the membranous part of the interatrial septum. [3] Bone morphogenetic protein (BMP) cell signaling plays a key role in various aspects of cardiac differentiation and morphogenesis.
(BMP) are multifunctional signaling molecules that are crucial for the development of AV nodes. BMP influences the development of the AV node via the Alk3 receptor (activin receptor kinase 3). The abnormalities seen with BMP and Alk3 are associated with certain cardiovascular diseases such as Ebstein`s anomaly and AV conduction disease. [7] He will not turn to the devil to solve a nodus until he has exhausted more legitimate resources. Although the AV node`s main function is to transmit impulses to the heart chambers, its nodal cells are also capable of generating their own electrical impulses (self-excitation). If the SA node or connected conductive fibers are dysfunctional and electrical signals are no longer transmitted, the AV node is able to independently generate pulses to maintain ventricle contractions. It is therefore often referred to as the secondary pacemaker. Under all the roofs of this distracted city lies the crux of a drama, not tragic, pushing towards a solution. A disturbance or delay in the transmission of electrical impulses from the atria to the ventricles is called an atrioventricular block or AV. AV blockage can occur as a result of a number of conditions affecting the AV node and/or AV bundle (of His), including ischemia, compression or inflammation of these structures.
The AV node receives two inputs from the right atrium: posterior via the crista terminalis and anterior via the interatrial septum. [8] The blood supply to the AV node comes from the branch of the atrioventricular node. The origin of this artery is most often (80-90% of hearts) a branch of the right coronary artery, the rest comes from the left circumflex artery. [4] [5] [6] This is related to the dominance of coronary artery circulation. In right-dominated individuals, blood is supplied by the right coronary artery, while in left-dominant individuals, it comes from the left circumflex artery. Heberden`s nodules are hard or bony swellings that can develop in the distal interphalangeal joints (PIDs) (the joints closest to the tips of the fingers and toes). [1] They are a sign of osteoarthritis and are caused by the formation of osteophytes (calcified spurs) of the articular cartilage in response to repeated trauma to the joint. [2] The atrioventricular node is an oblique oval collection of cells located in the wall of the posteroinferior region of the interatrial septum near the coronary sinus. It is located in the triangle of the atrioventricular node (or Koch`s triangle), which is the area posteriorly bounded by the right atrioventricular valve, the opening of the basal coronary sinus and the tendon of the inferior pyramidal space (Todaro`s tendon).
The atrioventricular node receives its arterial blood supply from the atrioventricular lymph node artery, a large arterial branch in the interventricular septum that originates from the right coronary artery. The normal intrinsic rate of fire of the AV node without stimulation (e.g. that of the SA node) is 40-60 times/minute. [13] This property is important because the loss of the conduction system in front of the AV node should further result in stimulation of the ventricles by the slower capacity of the pacemaker of the AV node. The atrioventricular node is the second of several components of the cardiac conduction system. This intrinsic conduction system is responsible for generating impulses for heart contractions and ensuring coordinated blood flow through the heart chambers. It consists of the following components: AV node cells are specialized heart muscle cells (cardiomyocytes), also known as nodal heart muscle cells, which are smaller than typical cardiomyocytes and lack intercalated discs. A distinctive feature of nodal cells is the ability of self-excitation, thanks to which they are able to independently generate spontaneous electrical impulses.
Nodal cells transmit these impulses through gap junctions to adjacent/perinodal cardiac myocytes. It is important to note that the electrical signals in the AV node are slightly delayed (by about 40 ms), which is due to the lower number of space junctions on these cells. The AV block can be classified according to the severity of the delay or line failure. A first-degree AV block describes an increased delay of the line and leads to a prolonged PR interval (> 200 ms) in an ECG – this interval represents the time between depolarization of the atria and depolarization of the ventricles. A second-degree AV block is defined as an increase in the PR interval with the appearance of drop beats. This phenomenon is the absence of ventricular contraction after atrial contraction, which is due to insufficient conduction from the atria to the ventricles. A third-degree AV block, also called a full AV block, occurs when there is a complete block of pulse transmission from the atria to the ventricles. In this case, ventricular contractions are maintained by the AV node (secondary pacemaker), while the atria continue to contract to the rhythm of the SA node, so that they become completely separate and independent of each other. “Nodus.” Merriam-Webster.com Dictionary, Merriam-Webster, www.merriam-webster.com/dictionary/nodus. Retrieved 11 October 2022. The atrioventricular node (also called the AV node) is a collection of specialized heart muscle cells grouped in a node inside the wall of the interatrial septum. It is an important component of the cardiac conduction system and is responsible for transmitting impulses emanating from the sinus node (SA) to the heart chambers.
An important feature of the AV node is its ability to slightly delay electrical signals, thus coordinating the contraction of the atria first and then the ventricles. Heberden`s nodules are more common in women than men, and there appears to be a genetic component involved in predisposition to the disease.