Objective.

The present study aimed at the investigation of the hemodynamic and electrophysiological parameters of the cardiac ventricles in dog (n=7) under the condition of antiorthostatic pose (AP). Methods. Using Prucka MacLab 2000 system, intraventricular blood pressures, isovolumic indexes, and cardiac output were measured. The activation and repolarization times determined from unipolar myocardial electrograms. AP was constructed by means of the transfer of canine body head first at an angle of the 45 (AP - 45ordm;) and 60 degrees (AP - 60ordm;), against to level. Results. Left ventricular systolic pressure was largely decreased (p<0.05) from thirtieth minute of the AP at an angle 45 degrees to thirtieth minute of the AP at an angle of 60 degrees as compared with level position. The maximal rate of the rise of pressure in the left ventricle was significantly (p<0.05) decreased with thirtieth minute of the AP - 45ordm;, and was reached to a higher degree of reduction on the thirtieth minute of the AP - 60ordm; as compared with level position. The dispersion of activation was increased (p<0.05) to a higher degree on the first and thirtieth minute of the AP - 45ordm;. Under AP the areas of the earliest (p<0.05) activation of the myocardium left and right of ventricles were observed in the apical subendocardial layers, but the latest zones of the excitation were found in the base of ventricles.

Conclusions: 

Thus, hemodynamic indices of the canine heart was impaired to a higher degree on the thirtieth minute of AP - 60ordm;. Under AP myocardium of the ventricles was described absence of the heterogeneity of repolarization.