The nexus in serial cross-sections of myocardium from cats subjected to hypovolemic shock. A three-dimensional interpretation.

Right ventricular papillary muscles from control cats and from cats subjected to hypovolemic shock were studied in cross-section, including serial sections, by electron microscopy. Loops of nexus and a redundant right angle nexus were followed through serial cross-sections in papillary muscles from the shock cats. These unusual nexus configurations were interpreted as a possible means of connecting perpendicular sheets of nexus, of interdigitating adjacent cells, and of providing slack to be taken up during the radial swelling of myocardial contraction. The flexibility of the intercalated disc which is implicit in this interpretation may explain the ability of cardiac myocytes to recover from the severe distortions adjacent to the intercalated disc which occur in myocardial zonal lesions, and perhaps, if they are reversible, in other lesions which occur in proximity to the intercalated disc.