Daniel Hale Williams was the first African American to perform heart surgery.
Daniel Hale Williams (1858-1931) was a pioneer in open heart surgery. In 1893, with the help of a surgical team, he saved a person who had been stabbed. Williams opened up the patient's chest, exposing the beating heart, and sewed the knife wound (which was a fraction of an inch from the heart). He did this without the aid of X-rays, blood transfusions, or anesthetics (numbing, pain-killing drugs).
Source: Carwell, Hattie. Blacks in Science: Astrophysicist to Zoologist, pp. 57-58.