[Pathogenesis of impaired cardiac electric stability in experimental hypodynamia].

The decreased ventricular fibrillation threshold (VFT) in the first 5 days of restriction results from stress-induced changes in myocardial autonomic innervation, as shown by elevated cardiac content of cAMP and lowered levels of cGMP, and a rise in the plasma concentrations of corticosterone and deoxycorticosterone. Ultimately, these changes enhance cardiomyocyte membranous permeability of calcium ions and, hence, lower VFT. Impaired cardiac electric stability in the late inactivity period (50 days) is also associated with the enhanced permeability of cardiomyocyte membranes; however, the nature of this phenomenon remains unclear and calls for further studies.