Ventricular fibrillation — uncontrolled fluttering of the heart that can lead to death within minutes — was a phenomenon well known as early as 1850. In fact, it was known that an electric current could start these abnormal contractions in a healthy heart.

In 1899, two Swiss researchers experimenting with dogs discovered that the fibrillation could also be stopped and normal beats restored in the same way, by shocking the heart. The New York Times reported the finding on July 3 of that year, but it would be almost a lifetime before anyone developed a practical application for it. When in 1948 The Times first mentioned the cardiac defibrillator — the device used to give the heart that life-saving jolt — it had just been invented, or rather reinvented in a jury-rigged version.