Edmund Hiram Sonnenblick (December 7, 1932 – September 22, 2007) was an American medical researcher and cardiologist. His studies of the function of cardiac muscle cells during the 1960s shaped the basis of both cardiovascular physiology and the modern treatment of cardiovascular disease, making possible the development of ACE inhibitors. In 1962, he was also credited as the first person to image the heart muscle under scientifically-controlled conditions using the electron microscope. Though Sonnenblick's ideas about the relationship between the structure and function of the human heart today constitute medical-scientific commonsense, they were utterly novel at the time.