The world's foremost expert in critical-focus laser surgery, Erica Sondheim made her debut in Iron Man #131, implanting a small pulse regulator in Dr. David Banner (an attempt to keep the Hulk at bay). The brilliant micro-surgeon returned in Iron Man #248 as part of Stark’s ace medical team. She then agreed to do the risky surgery that implanted the revolutionary biochip into Tony's spine, curing his paralysis.
At some point, she was kidnapped by henchmen working for wealthy businessman Darren Cross. Cross, who had been mutated by his specialized pacemaker, needed Dr. Sondheim to perform a risky heart transplant to save his life. The henchmen were pursued by Scott Lang, the new Ant-Man, who needed Erica's help to save his dying daughter, Cassie. After the ensuing battle resulted in Cross' death, Dr. Sondheim performed the procedure on Cassie and saved her life.
In Iron Man #284, she helped lead the team that froze Tony in cryogenic suspension. Following his thawing and resurrection, she became his personal physician. At some point, she was made Head of Stark Medical. She was dating Abe Zimmer.
Erica Sondheim was created by David Michelinie, John Byrne and Bob Layton in 1979 and first premiered in Marvel Premiere # 47.