Canadian, John Hopps invented the first cardiac pacemaker. Hopps was trained as an electrical engineer at the University of Manitoba and joined the National Research Council in 1941, where he conducted research on hypothermia. While experimenting with radio frequency heating to restore body temperature, Hopps made an unexpected discovery: if a heart stopped beating due to cooling, it could be started again by artificial stimulation using mechanical or electric means. This lead to Hopps' invention of the world's first cardiac pacemaker in 1950. His device was far too large to be implanted inside of the human body. It was an external pacemaker.