Morphometry and comparative histology of sinus and atrioventricular nodes in humans and pigs and their relevance in the prevention of nodal arrhythmias

Environmental Fe, Ti, Al, Cu, Hg, Bi, and Si Nanoparticles in the Atrioventricular Conduction Axis and the Associated Ultrastructural Damage in Young Urbanites: Cardiac Arrhythmias Caused by Anthropogenic, Industrial, E-Waste, and Indoor Nanoparticles

“…Samples were taken from the node, atrioventricular fascicle (AVF), and transitional, atrial, and ventricular overlay cells. − The AV node cells formed irregular cords surrounded by delicate fibrous tissues (Figure A–C). Purkinje cells/fibers (P-cells/fibers) showed abundant intermediate filaments, peripheral myofibrils, rounded mitochondria, and isolated nanoparticles both in the midst of the fibers and inside mitochondria (Figure D–F).…”

“…Autopsies were performed 3.7 ± 1.9 hours after sudden death (accidents, homicides, suicides). Sections of the heart from 11 cases included the atrioventricular node (AVN) extending in a region limited by the inferior vena cava, the central fibrous body, and the tricuspid valve carefully sectioned into blocks. − Blocks measuring 3 mm were cut with ceramic knives and we used plastic forceps, free from metal contamination, in a clean metal-free environment. The sections were fixed in 2% paraformaldehyde/2% glutaraldehyde in sodium phosphate buffer for TEM studies.…”

“…The atrioventricular node is at the core of this work. It is a key region responsible for delaying the passage of electrical signals to the ventricles, thereby protecting from fast depolarizations, increasing ventricular filling during diastole, and ultimately limiting the ventricular response during atrial tachyarrhythmias. − The AV node is targeted for causing effects by a range of abnormal conditions, including virus attacks, dysfunctional embryonic implantation, fetal and perinatal developmental alterations, and anatomical variations involving accessory atrioventricular pathways, coronary sinus aneurysms, or abnormal coronary veins. ,,,, Atrioventricular node reentrant tachycardia, typical and atypical atrial flutter, right-sided focal atrial tachycardia, and paroxysmal atrial fibrillation are common in Mexico and Latin American countries, requiring ablation procedures. , …”