"I am so sad to tell you that it is finished," said his brother Silvio Viotti in a message on the conductor's web site. "Marcello has finished his journey on this earth."
According to Agence-France Presse, Viotti had suffered a stroke. Surgery was performed to remove a blood clot in his carotid artery, but he never regained consciousness.
Born to Italian parents in the French-speaking section of Switzerland, Viotti held citizenship from several nations. He studied at the Lausanne Conservatory and launched his career in 1982 when he won the Gino Marinuzzi conducting competition in Italy.
Viotti served as chief conductor of the Turin Opera and the radio orchestras of Leipzig, Munich, and Saabr‹cken, as well as artistic director of the Lucerne State Theater. He was named music director of La Fenice in 2002. A guest conductor at many orchestras and opera companies, he made his Metropolitan Opera debut in 2000.
Among the conductor's upcoming engagements were Parsifal in Venice, Aida at the Vienna State Opera, La bohme at the Deutsche Oper Berlin, and La traviata at the Salzburg Festival.