Sinatra suffered cardiac arrest while on tour in Daytona, Fla.
Sinatra Jr. followed in his father's footsteps and began performing in clubs as a teen. At 19, he was kidnapped and held for ransom, but was later released and and his kidnappers were convicted.
Sinatra Jr.'s debut album, Young Love for Sale, came out in 1965. His final album, That Face!, was released in 2006. He mostly sang songs popularized by his father. At the time of his death, Sinatra Jr. was doing a tour called "Sinatra Sings Sinatra - The Centennial Celebration," which celebrated what would have been his father's 100th birthday last year.
Our condolences to the Sinatra family.