Six physiological parameters of cardio-vascular system of rabbits and ultrastructure of cardiomyocytes were investigated during two planetaty geomagnetic storms. At the initial and main phase of the storm the normal circadian structure in each cardiovascular parameter was lost. The disynchronozis was growing together with the storm and abrupt drop of cardia activity was observed during the main phase of storm. The main phase of storm followed by the destruction and degradation of cardiomyocytes. parameters of cardia activity became substuntially synchronized and characterised by circadian rhythm structure while the amplitude of deviations was stilt significant at the recovery stage of geomagnetic storm.