7. Helen Brooke Taussig

[Image from the National Institutes of Health]
Taussig was hired by the pediatric department at Johns Hopkins where she researched anoxemia and discovered that it is caused by a partial blockage of the pulmonary artery some times combined with a hole between the ventricles of the heart. She worked to develop a method to fix the defect and performed the first surgery on a human baby in 1946.
Taussig is also credited with pioneering the use of X-rays and fluoroscopy to get a non-invasive view of the changes of a baby’s heart and lungs.
She received her bachelor’s degree from the University of California at Berkeley in 1921 and later went on to study histology, bacteriology and anatomy at Harvard Medical School and Boston University, according to a Wikipedia article about her. She received her medical doctorate degree from Johns Hopkins University School of Medicine in 1927 where she served as a cardiology fellow for one year and a pediatrics intern for another two years.