Pantridge has been referred to as the grandfather of prehospital ALS. Working in Belfast, Northern Ireland, in the late 1950s and early 1960s, he supported the use of the relatively new resuscitative system of CPR for the early treatment of heart attack, but also saw there were limitations to its efficacy. Pantridge knew that the longer ventricular fibrillation was present, the less likely survival became. Hospital-based defibrillators were already being used in North America, but Pantridge doubted their impact, since data had shown that the majority of sudden cardiac arrests happened outside the hospital. It was known that most coronary deaths resulted from ventricular fibrillation. He believed that immediate correction of v-fib could and should be done at the scene of the event. However, a major problem was that defibrillators of the time could only be operated using main power supply. Using his research, he developed the first portable defibrillator-a svelte model that was powered by car batteries and weighed 70 kg. This led to his introduction of the mobile coronary care unit (MCCU), an ambulance with the new portable unit and staff to provide prehospital care. With this new tool, the Belfast treatment system became adopted throughout the world. Pantridge believed defibrillators needed to be as prevalent as fire extinguishers, and that if nonphysician responders could do CPR, then they could use defibrillators. To make the devices safer, Pantridge and his colleagues worked to improve the design, and after harnessing a miniature capacitor manufactured for NASA, he was able to create a defibrillator weighing only 3 kg. Pantridge's portable defibrillator would become a key tool in EMS, and after further refinement it has become the automated external defibrillator (AED), the cornerstone of response to cardiac arrests. Pantridge served on EMS Magazine's editorial advisory board for several years.