In a sample of 200 buildings built with the Great Soviet Panel prefabricated system in Santiago the Cuba, pathological damage and structural transformations carried out by the inhabitants are evidenced. Being necessary to evaluate a priori, the incidence of the aspects leading to potential seismic damages in the structural behavior of these buildings. To meet this objective, 16 hypothetical variants were elaborated, taking into account the statistical analysis of the diagnosis made, which are compared with the 4 variants of the original typologies. It is concluded that the aspects conducive to potential seismic damages have more repercussion in the change of the oscillation periods than in the seismic demand. Pathological damage is the one with the highest incidence in the increase in the fundamental periods of vibration, followed by the increase in weight and the openings of panels or slabs.