Conductor Seiji Ozawa has been hospitalized due to heart valve disease, his office said Thursday, adding that he will be replaced by another conductor at opera concerts later this month in Japan.

Ozawa, 82, had not been well since Feb. 27, and was diagnosed with aortic valve stenosis on March 2, the office said. He is expected to be in hospital for treatment and further tests for around one month.

"I am truly full of regret that I have become unable to conduct L'enfant et les sortileges. I deeply apologize to everyone who was looking forward to this," Ozawa said in a comment released on his academy's website.

Ozawa's former student Derrick Inoue will replace him to conduct Maurice Ravel's one-act opera at the concerts scheduled for this month in Tokyo, Kyoto and Aichi prefectures, the office said.