In cardiac physiology, preload is the amount of sarcomere stretch experienced by cardiac muscle cells, called cardiomyocytes, at the end of ventricular filling during diastole. Preload is directly related to ventricular filling. As the relaxed ventricle fills during diastole, the walls are stretched and the length of sarcomeres increases. Embriologia. Les cèl·lules cardíaques progenitores de l'epiblast embrionari migren fins a la làmina esplàncnica del mesoderma, on formen la regió cardiogènica. En ella es desenvolupen dues estructures tubulars que es fusionen i creen un únic tub cardíac primitiu, anomenat cor tubular, el qual té una capa externa i una interna i una porció proximal i una distal. Jun 04, 2021 · Multifocal Atrial Tachycardia (MAT) Overview. A rapid, irregular atrial rhythm arising from multiple ectopic foci within the atria. Most commonly seen in patients with severe COPD or congestive heart failure.; It is typically a transitional rhythm between frequent premature atrial complexes (PACs) and atrial flutter / fibrillation. Dec 19, 2021 · Atrial tachycardia is a broader term referring to any SVT initiated outside of the sinus node, and comprises FAT, MAT and atrial flutter. Atrial flutter is a separate entity to FAT but they are both forms of atrial tachycardia.