When cultured heart cells were exposed to X-XOD containing medium, the absolute values of APA, OS, Vmax, APD, MDP, TP decreased; the percentage of beating clusters reduced in single MEM medium, but the frequency increased sharply in Ba containing medium. The longer the period exposed to X-XOD, the more significant are the variations of the electrical and contractile indices. The effects of X-Mo was similar to that of X-XOD, but to a slightly less extent. Se significantly converted all the indices. It is concluded that X-XOD can induce serious injury of cultured myocytes, and so does the X-Mo, while Se can protect the cells from the injury.