Sergiu Comissiona (search), the Romanian-born conductor known for the spontaneity and flair that he brought to orchestras around the world, has died. He was 76.

The New York resident apparently died of a heart attack Saturday in an Oklahoma City (search) hotel room, hours before he was to serve as guest conductor for that city's philharmonic, officials said.

Comissiona held music directorships with some of North America's leading ensembles, including the Baltimore Symphony Orchestra (search), the Houston Symphony and the Vancouver Symphony. He also was music director of the New York City Opera.

"He elevated this orchestra to a level that had never been aspired to, and he created the platform from which to build a world-class orchestra," said John Gidwitz, former Baltimore Symphony Orchestra president.

Comissiona spent 15 years with the Baltimore orchestra, transforming it from a little-known ensemble into a nationally respected orchestra. He led the symphony on its first international tour and was at the helm when it made its first recordings.

"They were talking world-class when he was around. That had not happened before," said Melissa Zaraya, a BSO violinist for more than three decades.

Comissiona became principal conductor of the Romanian State Opera in his native country while in his early 20s. He was music director of the Haifa, Israel, Symphony from 1960-66; of the Goteborg, Sweden, Symphony from 1966-77, and was chief conductor of the Radio Philharmonic in Hilversum, Holland, starting in 1982.

He was also a permanent guest conductor with the George Enescu Philharmonic in the Romanian capital, Bucharest, whose artistic director described Comissiona's death as a heavy loss.

"He had an exceptional relationship with the orchestra and the choir," said Nicolae Licaret. "He was always diversifying the repertoire for the audiences and bringing lesser-known works."

Comissiona, who was born in Bucharest, emigrated to Israel in the 1950s and later to the United States.

He and his wife, the former Robinne Florin, became American citizens at Fort McHenry in Baltimore Harbor on July 4, 1976.

"I'm an American conductor, despite my accent," he told The Associated Press in a 1987 interview. "I love French music, German, Russian. I'm very young in this respect; I'm not ashamed of loving music. When I'm doing a moment of 'Pagliacci,' I'm ready to jump on the stage to be with them to sing. For me, every note in this opera is still very emotional."

From childhood, Comissiona wanted to conduct. "From 7 years, I started to go to concerts, collecting autographs and preparing the scores for the concert during the week and, of course, dreaming that the conductor would be sick. Then I would jump on the stage, make my debut and I would be famous.

"It did happen, with the Romanian State Ensemble — without poisoning the conductor," he said.

Comissiona became dizzy Friday evening as he was conducting a rehearsal with the Oklahoma City Philharmonic, said Joel Levine, music director of the philharmonic and a longtime friend of Comissiona's. Levine dropped Comissiona off at his hotel: "He said, 'Joel, don't worry. You won't be conducting tomorrow night. Would you turn out the lights please?"

A hotel worker found the conductor dead on Saturday morning.

Comissiona was scheduled to lead a concert with the cellist Yo-Yo Ma this week in Puerto Rico, said the maestro's niece, Jeanne Schayes.

He is survived by his wife of more than 50 years and a sister, Milly Barbalata.