Hi Alba83,
you may want to have a look at this guide
ec.europa.eu/employment_social/empl_portal/SSRinEU/Your%20social%20security%20rights%20in%20Slovakia_en.pdf
to the Slovak social security and health care system. Via
europa.eu/youreurope/citizens/health/planned-healthcare/hospitals/index
Your Europe: Finding the right healthcare provider abroad, where you can find more useful information.
Good luck!