The portable cardiac defibrillator was developed in Belfast by Professor Frank Pantridge. He had established that early treatment was key in surviving a cardiac arrest. In 1965 he installed his first version, like this one, in a Belfast ambulance. It weighed 70kg and operated from car batteries. By 1968 he had designed an instrument weighing only 3kg.
His work was backed up by clinical investigations and epidemiological studies. With these developments, the Belfast treatment system, was adopted throughout the world by emergency medical services.