The Cars frontman Ric Ocasek died from heart disease worsened by emphysema, the New York City medical examiner said.
The singer, 75, was found dead in a Manhattan apartment on Sunday.
Ocasek’s wife, the model and actress Paulina Porizkova, also revealed he was recovering from surgery at the time of his death.
Writing on Instagram, the 54-year-old said: “Ric was at home recuperating very well after surgery. Our two sons, Jonathan and Oliver, and I were making sure he was comfortable, ordering food and watching TV together.
“I found him still asleep when bringing him his Sunday morning coffee. I touched his cheek to rouse him. It was then I realised that during the night he had peacefully passed on.”
Porizkova, who met Ocasek while filming the music video for The Cars 1984 single Drive, added: “We appreciate the great outpouring of love.
“We, his family and friends, are completely and utterly devastated by his untimely and unexpected death and would appreciate the privacy to mourn in private.”
Last year Porizkova announced she and Ocasek had separated after 28 years of marriage.
Following the musician’s death, figures from across the industry paid tribute.
Canadian singer Bryan Adams praised Ocasek as a “great songwriter and singer” while Red Hot Chili Peppers bassist Flea, real name Michael Balzary, said he produced “perfect pop songs”.
Rock band The Cars were known for chart-topping hits in the late 1970s and 1980s including radio favourite Drive, Just What I Needed and Shake It Up.