Recording of electric impulses that are generated and spread in the cardiac tissue and control the contractions of the heart was made possible by the invention of string galvanometer (1903) by Willem Einthoven (1860-1927). Einthoven’s instrument, rewarded by the Nobel Prize in 1924, photographed the movements of a silver-coated thread that conducted the electric current generated by the patient’s heart in a strong magnetic field. Shortly after World War II, the Frank Sanborn Company in Cambridge, Massachussetts, founded in 1917, introduced direct recording by a heated stylus on heat-sensitive paper. In 1928, Sanborn presented the first portable EKG, still using photographic paper.
The oldest electrocardiograph in the Medical Museum collection is the single channel, portable Sanborn Viso-Cardiette (Model 572) from the 1950s. Originally, it belonged to the cardiologist Ladislav Filip (1898-1986), the Director and owner of a heart disease sanatorium in Podebrady and later Associate Professor at the Prague medical faculty.