The two conductors also spoke about recent tensions between Russia and the West. Mr. Gergiev — who was fired from engagements in the United States and Europe, as well as from the podium of the Munich Philharmonic, over his refusal to publicly condemn the war — defended his decision, saying that he was not a child, Mr. Heine recalled.
The Mariinsky declined to comment on Monday, and said it could not yet confirm Mr. Heine’s resignation. However, the company removed Mr. Heine’s biography from its website Monday evening.
Mr. Heine’s departure from the Mariinsky is an unexpected conclusion to his three-decade career in Russia, where he studied with renowned teachers and rose to become a conductor at one of the country’s most prestigious houses. And his exit is another blow to Russian cultural institutions, which are grappling with boycotts and cancellations by foreign groups as the country’s arts increasingly turn inward under Mr. Putin. Mr. Gergiev remains a critical figure in Mr. Putin’s campaign. Mr. Putin, during a televised meeting last month, asked Mr. Gergiev whether he was interested in the idea of uniting the Bolshoi Theater in Moscow with the Mariinsky, an arrangement that would take Russia back to the days of the czars.
“Russia is just going to be more and more closed,” said Simon Morrison, a music professor at Princeton University. “It’s going to revert more and more to its own true self, harsh as that might seem — a sealed-off, angry, paranoid and resentful feudal realm.”
Mr. Heine, who grew up in Cherry Hill, N.J., became interested in Russian culture as a teenager. He accompanied his mother, a pianist, to a performance in Moscow, and while there took cello lessons with a professor at the Moscow Conservatory.