The use of electrocardiograms (ECGs) in the study of heart conditions was begun at Mayo Clinic in 1914. The combined total ECGs made in 194 and 1915 was about 1000. In 1972, a technician carried out the 100,000th ECG performed in one single year. According to Wilbur Schumann, ECG Laboratory supervisor, 1972 was the first year in which the 100,000 mark had been exceeded.
Streamlining of processes had made it possible for the laboratory staff to keep abreast of growth. In 1963 a major change was made in laboratory procedures, including installation of a six-channel machine, which reduced the time required for the actual recording of the electrocardiogram from 12 to 15 minutes to 30 seconds.
At that time Dr. Ralph Smith, laboratory director, looked forward to additional changes including installation of a computer. Five years later (1968) this was realized but work still continues on modifications of procedures and equipment. The 30 second figure has now been reduced to 10 seconds during which the electrical impulses from the ECG are fed into the computer.
All electrocardiograms made since 1914—and the number is now more than a million and a half—are available. Current ones are kept in the area of the laboratory at A-1, Plummer Building, the rest are stored at Harwick Building.