The former Lions general manager was diagnosed with amyloidosis.
Ex-Lions general manager Matt Millen underwent a successful heart transplant Monday morning, according to NBC Sports' Peter King.
Millen, 60, was diagnosed with amyloidosis—a rare, life-threatening heart disorder—during summer 2017. He went into surgery at around 1 a.m. in a New Jersey hospital, and he was out by 8 a.m., per King.
Millen had been awaiting a heart donation for several weeks. A match was found on Sunday afternoon.
According to King, Millen's wife said the donor's heart was "a perfect match and he is doing well. The surgery went smoothly."