Heart measurement. Patient using an early electrocardiograph (ECG) to take a measurement from his skin of the electrical signals in his heart. The patient's left arm and leg are placed in buckets of salt water to improve the electrical contact. The ECG was brought into clinical use by Dutch physiologist Willem Einthoven in 1903. Einthoven successfully used an ECG device to diagnose heart disease; this work earned him the 1924 Nobel Prize for Medicine. The first public demonstration of an ECG had been by A.D. Waller (1856-1922) at the Royal Society in 1887. Photograph of an ECG in use at Cambridge, Britain, in 1908.