Almost 60 years later, Guy Knickerbocker was researching defibrillation in dogs and noticed by chance that when he pressed the electrode paddles firmly on the thorax, a simultaneous rise in arterial pressure resulted. This led to the rediscovery of external cardiac massage, today known as chest compression, which was reintroduced to patient care in 1958 by William Kouwenhoven Because this method did not require scalpels or significant technical expertise, it became widely taught and quickly eclipsed the open-thorax approach.