El sistema especializado de conducción eléctrico del corazón. Los nodos del corazón y el sistema His-Purkinje. Sustrato anatómico de las vías accesorias

Abstract

The specialized electrical conduction system of the heart. The heart nodes and the His-Purkinje system. Anatomical underpinnings of the accessory pathwaysThe muscular architecture of the heart myocardium is mainly composed of muscle cells, or cardiomyocytes, that are responsible for myocardial contraction as well as an interstitial space with a component of collagen-producing cells, or fibroblasts, surrounded by an extracellular matrix of connective tissue. Small cell groups predominantly located in the atria have neuroendocrine characteristics. In order to activate of the striated myocardium and excitation-contraction coupling through transmembrane action potential, the presence of specialized cells of the specific conduction system is necessary. The process and sequence of activation of the heart chambers occurs through the specific conduction system and is modulated by sympathetic and parasympathetic fibers of the neurovegetative system, which exercise autonomous control of it.The atrioventricular conduction system is composed of specialized myocytes and has an atrial component: the sinoatrial node and atrioventricular node, which are in contact with the atrial myocardium. Next, the bundle of His crosses the central fibrous body and divides into two bundles or branches—the left and the right—which branch into the ventricles, forming what is known as Purkinje fibers. The bundle of His and its branches are surrounded by a layer of connective tissue that is lost in the Purkinje fibers, allowing them to establish direct contact with the ventricular myocardium. Detailed knowledge of the specific conduction tissue is necessary to understand normal heart rhythm and the anatomical and electrical underpinnings that constitute heart arrhythmias.