The interelectronic-interaction effect on the transition probabilities in
high-Z He-like ions is investigated within a systematic quantum electrodynamic
approach. The calculation formulas for the interelectronic-interaction
corrections of first order in 1/Z are derived using the two-time Green function
method. These formulas are employed for numerical evaluations of the magnetic
transition probabilities in heliumlike ions. The results of the calculations
are compared with experimental values and previous calculations