The youngster made his debut for the Serie A outfit aged 18, but doctors last year discovered that he had an irregular heartbeat.
Natalino suffered a heart attack and required emergency surgery in February. He was hoping to return to football, but has now decided to hang up his boots for good.
"I was told that I could still be passed fit to play abroad, but my personal doctor said it's really not wise to push the heart too hard," he told La Gazzetta dello Sport.
"I am helping out my father in our family football school, Virtus Sambiase, and try to give advice to the young players. I also spend time at the gym set up by my uncle, who died in a tragic cycling accident.
"Life goes on. It could've gone better, but it could also have been much worse. Thanks to everyone anyway and especially to Inter, who continue to stay close to me. I am sad in one way, but on the other I am happy. I am ok, that is what counts."
Natalino made two senior appearances for Inter and completed loan stints with Verona and Crotone.