Results of our recent search for superfast line-profile variations (LPVs) in spectra of the bright OBA stars HD 93521 (O9.5III), $\rho$ Leo (B1Iab), $\alpha^2$ CVn, and $\gamma$\,UMi are presented. The spectra were obtained using the multi-mode focal reducer SCORPIO on the Russian 6-m telescope. Both regular LPVs with periods from 2 to 90 minutes and non-regular LPVs on time-scales of seconds were detected. Such short-term spectral variability in massive OBA stars has not been studied systematically before. These studies can be crucial for understanding the physics of type-II supernova and for improved modelling of stellar evolution.